Prasanna

Students can Download Maths Chapter 5 Geometry Ex 5.3 Questions and Answers, Notes Pdf, Samacheer Kalvi 7th Maths Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 5 Geometry Ex 5.3

Question 1.
Draw a line segment of given length and construct a perpendicular bisector to each line segment using scale and compass
(a) 8 cm
(b) 7 cm
(c) 5.6 cm
(d) 10.4 cm
(e) 58 cm
Solution:
(a) 8 cm
Construction :

Step 1: Drawn a line. Marked two points A and B on it so that AB = 8 cm
Step 2: Using compass with A as centre and radius more than half of the length of AB, drawn two arcs of the same length one above AB and one below AB
Step 3: With the same radius and B as centre drawn two arcs to cut the arcs drawn in step 2. Marked the points of intersection of the arcs as C and D.
step 4: Joined C and D, CD intersect AB. Marked the point of intersection as ‘O’.
CD is the required perpendicular bisector of AB.

(b) 7 cm
Construction :

step 1: Drawn a line and marked points A and B on it so that AB = 7 cm.
step 2: Using compass with A as centre and radius more than half of the length of AB drawn two arcs of same length one above AB and one below AB.
step 3: With the same radius and B as centre drawn two arcs to cut the already drawn arcs in step 2. Marked the intersection of the arcs as C and D
step 4: Joined C and D, CD is the required perpendicular bisector of AB.

(c) 5.6 cm.
Construction :

Step 1: Drawn a line and marked two points A and B on it so that AB = 5.6cm
Step 2: Using compass with A as centre and radius more than half of the length of AB, drawn two arcs of the same length, one above AB and one below AB
Step 3: With the same radius and B as centre drawn two arcs to cut the arcs drawn in step 2 and marked the points of intersection of the arcs as C and D
Step 4: Joined C and D. CD intersects AB. Marked the point of intersection as ‘O’CD is the required perpendicular bisector of AB.
Now ∠AOC = 90° AO = BO = 2.8 cm

(d) 10.4 cm
Construction :

Step 1: Drawn a line and marked two points A and B on it so that AB = 10.4 cm.
Step 2: Using compass with A as centre and radius more than half of the length of AB, drawn two arcs of same length one above AB and one below AB.
Step 3: With the same radius and B as centre drawn two arcs to cut the arcs drawn in step 2 and marked the points of intersection of the arcs as C and D.
Step 4: Joined C and D. CD intersects AB. Marked the points of intersection as O. CD is the required perpendicular bisector.
Now ∠AOC = 90° ; AO = BO = 5.2 cm

(e) 58 mm

Construction :

Step 1: Drawn a line. Marked two points A and B on it so that
AB = 5.8 cm = 58 mm.
Step 2: Using compass with A as centre and radius more than half of the length of AB, drawn two arcs of the same length one above AB and one below AB.
Step 3: With the same radius and B as centre drawn two arcs to cut the arcs of drawn in step 2. Marked the points of intersection of the arcs as C and D.
Step 4: Joined C and D. CD intersects AB. Marked the point of intersection as O. CD is the required perpendicular bisector. ∠AOC = 90°
AO = BO = 2.9 cm

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Tamilnadu Samacheer Kalvi 6th Maths Solutions Term 1 Chapter 6 Information Processing Ex 6.3

Question 1.
How many Triangles are there in each of the following figures?

Solution:
(i) The single portions A, B, C, D, E, F, G and H are 8 triangles.
Taking the combination of 2 E & F, F & G & H and E & 11 are 4 triangles.
There are 8 + 4 = 12 triangles.

(ii) The smaller portions A, B, C, D, E, F, G and H are 8 triangles.
Combining 2 at a time B & C, D & F, F & G, A & H are 4 triangles.
Taking 4 at a time
Combination of B, C, D and E; D, E, F and G; F, G, H and A; H, A, B and C are 4 triangles.
Total triangles = 8 + 4 + 4 = 16.

(iii) Every part A, B, C, D, E, F, G, H, I, J, K, L, M, N, O and P are 16 triangles.
Combining two at a time. A & B, B & C, C & D, D & A, J & K, L & M, N & O, P & I are 8 triangles.
Taking the combination of 4, we have I, J, E & A; K, L, F and B, M, N, G and C, P, O, H and D are 4 triangles.
Taking 8 parts together we have QRS, RST, STQ, and TRQ are 4 triangles.
Total triangles = 16 + 8 + 4 + 4 = 32 triangles.

(iv)

Taking smaller triangles we have AFB, BFG, BGC, CGH, HCD, DHI, DIE, EIJ, EJAand AJF ⇒ 10 triangles.
Taking the combination of 2.
CGD, CID, DJE, DHE, EIA, EFA, AGB, AJB, BHC and BFC are 10 triangles.
Combining 3 at a time we have CED, DAE, EBA, ACB, BDC, CEF, DBJ, GDA, EBH, ACI ⇒ 10 triangles.
Other triangles are BCE, CAD, DBE, ADB and ACE are 5 triangles.
Total 10 + 10 + 10 + 5 = 35 triangles.

Question 2.
Find the number of dots in the tenth figure of the following pattern.

Solution:
(i) The number of dots given are 1, 3, 6, 10, 15,…

1st number = 1
2nd number = 1 + 2 = 3
3rd number = 3 + 3 = 6
4th number = 6 + 4 = 10
5th number = 10 + 5 = 15
6th number will be 15 + 6 = 21
7th number will be 21 + 7 = 28
8th number will be 28 + 8 = 36
9th number will be 36 + 9 = 45
10th number will be 45 + 10 = 55
Number of dots in the 10th figure = 55
(ii) The number of dots given are 1, 4, 9, 11, 16, 25,…
The no. of dots are in the pattern 1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, …… 10 × 10
The number of dots in the 10th figure = 100.

Question 3.

(i) Draw the next pattern.
(ii) Prepare a table for the number of dots used for each pattern.
(iii) Explain the pattern.
(iv) Find the number of dots in the 25th pattern.
Solution:

First number is 2
2nd number is 2 + 3 = 5
3rd number is 5 + 4 = 9
4th number is 9 + 5 = 14
5th number is 14 + 6 = 20
(iv) Number of dots in the 25th pattern is

The number of dots in the 25th pattern = 350.

Question 4.
Count the number of squares in each of the following figures?

Solution:

Smaller squares 4 × 4 = 16 (As numbered).
As a whole bigger = 4
Total squares = 20

As we see in the figure in the middle 1, 2, 3, and 4 are 4 small squares.
Also, we have 9 and 10 = 2 big squares.
Outer squares 5, 6, 7, & 8 = 4.
Total = 4 + 4 + 1 + 1 = 10 squares.

Question 5.
How many circles are there in the following figure?

Solution:

There are 7 Circles.

Question 6.
Find the minimum number of straight lines used in forming the following figures.

Solution:

There are 5 horizontal lines and 5 vertical lines.
Total of 10 lines minimum needed.

There are 12 straight lines used which is minimum.

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 1 Number System Additional Questions

Additional Questions and Answers

Exercise 1.1

Question 1.
When Malar woke up her temperature was 102°F. Two hours later it was 3° lower, what was her temperature then?
Solution:
Initially Malar’s temperature = 102°F
After two hours it lowered 3° ⇒ -3°F
Here present temperature = 102° + (-3°) = 99°F

Question 2.
An elevator is on the twentieth floor. It goes down 11 floors and then up 5 floors.
What floor is the elevator on now?
Solution:
Present location of the elevator = 20th floor
If it goes down 11 floor ⇒ (-11)
= 20 +(-11) = 9th floor
If it goes up 5 floor ⇒ 9 + 5
= 14th floor

Question 3.
16 + ___ = 16. The property expressed here is ____
Solution:
16 + 0 = 16.
0 is the additive identity on integers.

Exercise 1.2

Question 1.
Roman civilization began in 509 BC and ended in 476 AD. How long did Romans civilization last.
Solution:
From the start of common era no. of years upto 476
AD = 476
From 509 BC to start of common era years = 509
Total years Roman civilization last = 476 + 509 = 985 years.

Question 2.
A submarine was situated 450 feet below sea level. If it descends 300 feet. What is its new position?
Solution:
Position of submarine = -450 ft.
Again it descends 300 feet ⇒ -300 feet
∴ New position = —450 + (-300) = -750 ft.
∴ It was 750 feet below sea level.

Question 3.
In January the high temperature recorded was 90°F and the low temperature was -2°F. Find the difference between the high and the low temperatures?
Solution:
The high temperature recorded = 90°F
The low temperature recorded = -2°F
Difference = 90°F – (-2°F)
= 90°F + (Additive inverse of -2°F)
= 90°F + (+2°F) = 92°F

Exercise 1.3

Question 1.
Ani is scuba diving. She descends 5 feet below sea level. She descends the same distance 4 more times. What is Anis final elevation?
Solution:
Ani descends 5 feet below sea level once she descends 4 more times
∴ She descends (5 × 4) + 5 feet in total = 20 + 5 = 25 feet below sea level

Question 2.
The price of a plant reduced ₹ 6 per week for 7 weeks. By how much did the price of the plant change over the 7 weeks?
Solution:
The price of plant reduced in a week = ₹ 6
∴ The price reduced in 7 weeks = 7 × 6 = 42

Question 3.
The product of three integers is -3. Determine all of the possible values for the three factors?
Solution:
Product of three integers = -3
Possible factors are (1 × -1 × 3), (-1 × -1 × -3), (1 × 1 × -3)

Exercise 1.6

Question 1.
Simplify the following using suitable properties.
(a) (-1650) × (-2) + (-1650) × (-98)
(b) (9150 × 405) – (8150 × 405)
Solution:
(a) (-1650) × (-2) + (-1650) × (-98)
= 1650 [(-1) × (-2) + (-1) × -98] = 1650 (2 + 98) [Distributive property]
= 1650 × 100= 1,65,000

(b) (9150 × 405) – (8150 × 405)
= 405 (9150 – 8150) = 405 × 1000
= 4,05,000

Question 2.
Which is greater: (9 + 7) × 1000 or 9 + 7 × 1000?
Solution:
(9 + 7) × 1000 = 16 × 1000 = 16,000
9 + 7 × 1000 = 9 + 7000 = 7,009
16,000 > 7009
∴ (9 + 7) × 1000 > [9 + 7 × 1000]

Question 3.
Simiplify: 80 ÷ [240 ÷ (-24)] + 7
Solution:
We have
80 ÷ [240 ÷ (-24)] + 7
= 80 ÷ \(\left[\frac{240}{-24}\right]\) + 7
= 80 ÷ (-10) + 7 = \(-\left[\frac{80}{10}\right]\) + 7 = (-8) + 7 = -1

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 1 Number System Ex 1.6

Miscellaneous Practice Problems

Question 1.
What should be added to -1 to get 10?
Solution:
(-1) + a number = 10
∴ The number = 10 + 1 = 11

Question 2.

Solution:

Question 3.
Substract 94860 from (-86945)
Solution:
-86945 – (94860) = -86945 + (Additive inverse of 94860)
= -86945 + (-94860) = -1,81,805

Question 4.
Find the value of (-25) + 60 + (-95) + (-385)
Solution:
(-25) + 60 + (-95) + (-385) = 35 + (-95) + (-385) = -60 + (-385) = -445

Question 5.
Find the sum of (-9999) (-2001) and (-5999).
Solution:
(-9999) + (-2001) + (-5999) = -12,000 + (-5999) = -17,999

Question 6.
Find the product of (-30) × (-70) × 15.
(-30) × (-70) × 15 = (+2100) × 15 = 31,500

Question 7.
Divide-72 by 8.
Solution:
\(\frac{-72}{8}\) = -9

Question 8.
Find two pairs of integers whose product is +15.
Solution:
(i) (+3) × (+5)
(ii) (-3) × (-5)

Question 9.
Check the following for equality.
(i) (11 + 7) + 10 and 11 + (7 + 10)
(ii) (8 – 13) × 7 and 8 – (13 × 7)
(iii) [(-6) – (+8)] × (-4) and (-6) – [8 × (-4)]
(iv) 3 × [(-4) + (-10)] and [3 × (-4) + 3 × (-10)]
Solution:
(i) LHS = (11 + 7) + 10 = 18 + 10 = 28
RHS = 11 + (7 + 10)
= 11 + (17) = 28
LHS = RHS
∴ (11 + 7) + 10 = 11 + (7 + 10)

(ii) LHS = (8 – 13) × 7 = -5 × 7 = -35
RHS = 8 – (13 × 7) = 8 – 91 = -83
LHS ≠ RHS
∴ (8 – 13) × 7 ≠ 8 – (13 × 7)

(iii) LHS = [(-6) – (+8)] × (-4) = [(-6) + (-8)] × (-4) = (-14) × (-4) = +56
RHS = (-6) – [8 × (-4)] = -6 – (-32)
= -6 + (+32) = +26
LHS ≠ RHS
∴ [(-6) – (+8)] × (-4) ≠ (-6) – [8 × (-4)]

(iv) LHS = 3 × [(-4) + (-10)] = 3 × (-14) = -42
RHS = [3 × (-4) + 3 × (-10)] = (-12) + (-30) = -42
LHS = RHS
3 × [(-4) + (-10)] = [3 × (-4) + 3 × (-10)]

Question 10.
Kalaivani had ₹ 5000 in her bank account on 01.01.2018. She deposited ₹ 2000 in January and withdrew ₹ 700 in February. What was Kalaivani’s bank balance on 01.04.2018, if she deposited ₹ 1000 and withdraw ₹ 500 in March.
Solution:
Initial bank balance = ₹ 5000 ; Total deposits: January : ₹ 2000 ; March : ₹ 1000
Total deposits upto March = ₹ 5000 + ₹ 2000 + ₹ 1000 = ₹ 8000
Amount withdrawn: February : ₹ 700 (-)
March : ₹ 500 (-)
∴ Total amount withdrawn = (-700) + (-500) ₹ -1200
Net bank balance = ₹ 8000 – ₹ 1200 = ₹ 6800

Question 11.
The price of an item x increases by ₹ 10 every year and an item y decreases by ₹ 15 every year. If in 2018, the price of x is ₹ 50 andy is ₹ 90, then which item will be costlier in the year 2020?
Solution:
Amount increases for x every year = ₹ 10.
Price ofx in 2018 = ₹ 50 ; Price of x in 2019 = ₹ 50 + ₹ 10 = ₹ 60
Price of x in 2020 = ₹ 60 + ₹ 10 = ₹ 70 Amount decreases for y per year = ₹ 15
Price of y in 2018 = ₹ 90
Price of y in 2019 = ₹ 90 – ₹ 15 = ₹ 75
Price of y in 2020 = ₹ 75 – ₹ 15 = ₹ 60
Here 70 > 60. Item x will costlier in year 2020.

Question 12.
Match the statements in Column A and Column B.

Solution:
1. – d
2. – a
3. – e
4. – c
5. – b

Challenge Problems

Question 13.
Say True or False.
(i) The sum of a positive integer and a negative integer is always a positive integer.
(ii) The sum of two integers can never be zero
(iii) The product of two negative integers is a positive integer.
(iv) The quotient of two integers having opposite sign is a negative integer.
(v) The smallest negative integer is -1.
Solution:
(i) False
(ii) False
(iii) True
(iv) True
(v) False

Question 14.
An integer divided by 7 gives a result -3. What is that integer?
Solution:
According to the problem \(\frac{\text { An integer }}{7}\) = -3
∴ The integer = -3 × 7
The required integer = -21.

Question 15.
Replace the question mark with suitable integer in the equation.

Solution:

Question 16.
Can you give 10 pairs of single digit integers whose sum is zero?
Solution:
1 + (-1) + 2 + (-2) + 3 + (-3) + 4 + (-4) + 5 + (-5) = 0

Question 17.
If P = -15 and Q = 5 find (P – Q) – (P + Q).
Solution:
Given P = 15 ; Q = 5

Question 18.
If the letters in the English alphabets A to M represent the number from 1 to 13 respectively and N represents 0 and the letters O to Z correspond from -1 to -12, find the sum of integers for the names given below. For example,
MATH → Sum → 13 + 1 – 6 + 8 = 16
(i) YOUR NAME
(ii) SUCCESS
Solution:
Given

(i) My name LEENA → 12 + 5 + 5 + 0 + 1 = 23
(ii) SUCCESS → (-5) + (-7) + 3 + 3 + 5 + (-5) + (-5)
= -12 + 6 + 5 + (-10) = -6 + 5 + (-10) = (-1) + (-10)
= -11

Question 19.
From a water tank 100 litres of water is used every day. After 10 days there is 2000 litres of water in the tank. How much water was there in the tank before 10 days?
Solution:
Water used for one day = 100 litres.
Water used for 10 days = 100 × 10 = 1000 litres.
After 10 days water left in the tank = 2000 litres
Initially amount of water will be = 2000 + 1000 = 3000 litres

Question 20.
A dog is climbing down into a well to drink water. In each jump it goes down 4 steps. The water level is in 20th step. How many jumps does the dog take to reach the water level?
Solution:
The water in the well is at 20th step.
For each jump the dog goes low 4 steps. 5
∴ Number of jumps the dog to reach the water = \(\frac{20}{4}\) = 5 jumps

Question 21.
Kannan has a fruit shop. He sells 1 dozen banana at a loss of ? 2 each because it may get rotten next day. What is his loss?
Solution:
1 dozen = 12 bananas
For 1 banana loss = ₹ 2
For 12 bananas loss = ₹ 2 × 12 = ₹ 24

Question 22.
A submarine was situated at 650 feet below the sea level. If it descends 200 feet, what is its new position?
Solution:
Position of submarine = 650 feet below sea level = -650 feet
Again the depth it descends = 200 feet below = – 200 feet
∴ Position of submarine = (-650) + (-200) = -850 feet
The submarine will be 850 feet below the sea level.

Question 23.
In a magic square given below each row, column and diagonal should have the same sum. Find the values of x, y, and z.

Solution:
Column total = Row total = diagonal total
∴ 1 + y + (-6) = (-10) + (-3) + 4
y + (- 5) = -13 + 4
y = -9 + 5
y = -4
So 1 + (-10) + x = y + (-3) + (-2)
-9 + x = (-4) + (-3) + (-2)
-9 + x = -9
x = -9 + 9
x = 0
Now x + (-2) + z = (-10) + (-3) + 4
0 + (-2) + z = (-13) + 4
-2 + z = -9
z = -9 + 2 = -7
z = -7
∴ x = 0, y = -4, z = -7

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 5 Geometry Ex 5.2

Question 1.
From the figures name pair of angles.

Solution:
(i) m and n are parallel lines and l is the transversal.
∴ ∠1 and ∠2 are exterior angles on the same side of the transversal.

(ii) m and n are parallel lines and l is the transversal
∠1 and ∠2 are alternate exterior angles.

(iii) m and n are parallel lines l is the transversal
∠1 and ∠2 are corresponding angles.

(iv) m and n are parallel lines l is the transversal.
∠1 and ∠2 are interior angles on the same side of the transversal.

(v) m and n are parallel lines and l is the transversal.
∠1 and ∠2 are alternate interior angles.

(vi) o and q are parallel lines and n is the transversal.
∠1 and ∠2 are corresponding angles.

Question 2.
Find the measure of angle x in each of the following figures.

Solution:
(i) m and n are parallel lines and l is the transversal.
x° and 35° are corresponding angles and so they are equal.
∴ x = 35°

(ii) m and n are parallel lines and l is the transversal.
∴ x = 65°
[∴ corresponding angles are equal].

(iii) n and m are parallel lines and l is the transversal.
Corresponding angles are equal
∴ x = 145°

(iv) m and n are parallel lines and l is the transversal.
Corresponding angles are equal
∴ x = 135°

(v) m and n are parallel lines, l is the transversal perpendicular to both the lines
∴ x = 90°

Question 3.
Find the measure of angles in each of the following figures.

Solution:
(i) m and n are parallel lines. l is the transversal. Then alternate interior angles are equal
∴ y = 28°

(ii) m and n are parallel lines. l is the transversal. Alternate exterior angles are equal
∴ y = 58°

(iii) m and n are parallel lines. l is the transversal.
Alternate interior angles are equal
∴ y = 123°

(iv) m and n are parallel lines . l is the transversal
alternate exterior angles are equal.
∴ y = 108°

Question 4.
Find the measure of angle z in each of the following figures.

Solution:
(i) m and n are parallel lines l is the transversal
Then interior angles that lie on the same side of the transversal are supplementary
∴ z + 31° = 180°
z + 31° – 31° = 180° – 31°
z = 149°

(ii) m and n are parallel lines, l is the transversal
Interior angles that lie on the same side of the transversal are supplementary
∴ z + 135° = 180°
z + 135° – 135° = 180° – 135°
z = 45°

(iii) m and n are parallel lines l is the transversal exterior angles that lie on the same side of the transversal are supplementary.
∴ z + 79° = 80°
z + 79° – 79° = 180° – 79°
z = 101°

(iv) m and n are parallel lines and l is the transversal. Corresponding angles are equal
z + 22° = 180°
z + 22° – 22° = 180° – 22°
z = 158°

Question 5.
Find the value of angle ‘a’ in each of the following figures

Solution:
(i) m and n are parallel lines. l is the transversal
∴ Corresponding angles are equal

(ii) m and n are parallel lines l is the transversal
Exterior angles that lie on the same side of the transversal are supplementary
∴ (4a + 13) + 135° = 180°
4a + 13 + 135° = 180°
4a +148° = 180°
4a + 148° – 148° = 180° – 148°
4a = 32°

(iii) m and n are parallel lines l is the transversal
∴ Alternate interior angles are equal

(iv) m and n are parallel lines l is the transversal which is perpendicular to m and n

Question 6.
Find the value of the angle x in both the figures

Solution:
(i) m and n are parallel lines. l is the transversal
∴ Alternate interior angles are equal

(ii) m and n are parallel lines. l is the transversal
Exterior angles on the same side of the transversal are supplementary

Question 7.
Anbu has marked the angles as shown below in (i) and (ii). Check whether both of them are correct. Give reasons

Solution:
(i) m and n are parallel lines. l is the transversal.
Interior angles on the same side of the transversal are supplementary. But here it is 75 + 75 ≠ 180°
105 + 105 ≠ 180°
∴ Angles marked are not correct

(ii) m and n are parallel lines. l is the transversal.
Corresponding angles must be equal. So here the marking is wrong.

Question 8.
Mention two real life situations where we use parallel lines.
Solution:
Two angles of a wall in a building Cross rods in a window.

Question 9.
Two parallel lines are intersected by a transversal. What is the minimum number of angles you need to know to find the remaining angles. Give reasons.
Solution:

When two parallel lines are intersected by a transversal, we need a minimum of a single angle to find the remaining angle.
Using the concept of linear pair of angles, we can final one more angle.
By the concepts of corresponding angles, alternate interior angles and alternate , exterior angles we could find all other angles.

Objective Type Questions

Question 10.
A line which intersects two or more lines in different points is known as
(i) parallel lines
(ii) transversal
(iii) non-parallel lines
(iv) Intersecting lines
Solution:
(ii) Transversal

Question 11.
In the given figure angles a and b are
(i) alternate exterior angles
(ii) corresponding angles
(iii) Alternate interior angles
(iv) Vertically opposite angles
Solution:
(i) alternate exterior angles

Question 12.
Which of the following statement is ALWAYS TRUE when parallel lines are cut by a transversal
(i) corresponding angles supplementary
(ii) alternate interior angles supplementary
(iii) alternate exterior angles supplementary
(iv) interior angles on the same side of the transversal are supplementary
Solution:
(iv) Interior angles on the same side of the transversal are
supplementary.

Question 13.
In the diagram what is the value of angle x?
(i) 43°
(ii) 44°
(iii) 132°
(iv) 134°
Hint:

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Tamilnadu Samacheer Kalvi 6th Maths Solutions Term 1 Chapter 6 Information Processing Ex 6.2

Question 1.
In the following magic triangle, arrange the numbers from 1 to 6, so that you get the same sum on all its sides.

Solution:
Step 1: Complete the corners with smaller numbers 1, 2 and 3.

Step 2: The side having smallest numbers 1 & 2 are to be filled with the greatest number 6, the second smallest 1 & 3 side to be filled with the second largest 5 at the middle and so on.

The magic sum is 1 + 6 + 2 = 2 + 4 + 3 = 3 + 5 + 1 = 9. Some other ways are given below.

The magic sum = 1 + 6 + 3 = 3 + 2 + 5 = 5 + 4 + 1 = 10.

The magic sum 6 + 1 + 4 = 4 + 5 + 2 = 2 + 3 + 6 = 11.

The magic sum 4 + 3 + 5 = 5 + 1 + 6 = 6 + 2 + 4 = 12.

Question 2.
Using the numbers from 1 to 9
(i) Can you form a magic triangle?
(ii) How many magic triangles can be formed?
(iii) What are the sums of the sides of the magic triangle?

Solution:
(i) Yes, we can form
(ii) 5
(iii)


Sums are 17, 19, 20, 21 and 23.

Question 3.
Arrange the odd numbers from 1 to 17 without repetition to get a sum of 30 on each side of the magic triangle.

Solution:
The odd numbers between 1 to 17 are 1, 3, 5,7,9,11,13,15,17.
Step 1: Place the smaller numbers 1, 3, 5 on the comers.

Step 2: Arrange another set of smaller numbers 7, 9 and 11 on each side.

Step 3: Arrange the remaining numbers 13,15,17 to give the total 30.

Magic sum = 30.

Question 4.
Put the numbers 1, 2, 3, 4, 5, 6 and 7 in the circles so that each straight line of three numbers add up to the same total.

Solution:
Here there is even number of terms. Also we know that 1 + 6 = 7, 2 + 5 = 7, 3 + 4 = 7; so placing 7 at the centre, and the pairs (1, 6) (2, 5) and (3, 4) at. the opposite ends we get, the answer.

Question 5.
Place the number 1 to 12 in the 12 circles so that the sum of the numbers in each of the six lines of the star is 26. Use each number from 1 to 12 exactly once. Find more possible ways.

Solution:
The given star can be viewed as two magical triangular as.

Now the required arrangement is

Some other arrangements are

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 1 Number System Ex 1.5

Question 1.
One night in Kashmir, the temperature is -5°C. Next day the temperature is 9°C. What is the increase in temperature?
Solution:
Temperature in the first day = -5°C
Temperature in the next day = 9°C
∴ Increase in temperature = 9°C – (-5°C)
= 9°C + (+5°C) = 14°C

Question 2.
An atom can contain protons which have a positive charge (+) and electrons which have a negative charge (-). When an electron and a proton pair up, they become neutral (0) and cancel the charge at. Now determine the net charge:
(i) 5 electrons and 3 protons → -5 + 3 = -2 that is 2 electrons \(\ominus\ominus\)
(ii) 6 protons and 6 electrons →
(iii) 9 protons and 12 electrons →
(iv) 4 protons and 8 electrons →
(v) 7 protons and 6 electrons →
Solution:
(ii) 6 protons and 6 electrons → (+6) + (-6) = 0
(iii) 9 protons and 12 electrons → (+9) + (-12) = 9-12 = -3 ⇒ 3 electrons \(\ominus\ominus\ominus\)
(iv) 4 protons and 8 electrons → (+4) + (-8) = +4 – 8 = -4 ⇒ 4 electrons \(\ominus\ominus \ominus\ominus\)
(v) 7 protons and 6 electrons → (+7) + (-6) = +1 = 1 proton \(\oplus\)

Question 3.
Scientists use the Kelvin scale (K) as an alternative temperature scale to degrees Celsius (°C) by the relation T°C = (T + 273)K. Convert the following to Kelvin:
(i) -275°C
(ii) 45°C
(iii) -400°C
(iv) -273°C
Solution:
(i) -275°C = (-275 + 273)K = -2K
(ii) 45°C = (45 + 273)K = 318 K
(iii) -400°C = (-400 + 273)K = -127 K
(iv) -273°C = (-273 + 273) K = 0K

Question 4.
Find the amount that is left in the student’s bank account, if he has made the following transaction in a month. His initial balance is ₹ 690.
(i) Deposit (+) of ₹ 485
(ii) Withdrawal (-) of ₹ 500
(iii) Withdrawal (-) of ₹ 350
(iv) Deposit (+) of ₹ 89
(v) If another ₹ 300 was withdrawn, what would the balance be?
Solution:
(i) Initial balance of student’s account = ₹ 690
Deposited amount = ₹ 485 (+)
∴ Amount left in the account = ₹ 690 + ₹ 485 = ₹ 1175

(ii) Balance in the account = ₹ 1175
Amount withdrawn = ₹ 500 (-)
Amount left = ₹ 1175 – ₹ 500 = ₹ 675

(iii) Balance in the account = ₹ 675
Amount withdrawn = ₹ 350 (-)
Amount left = ₹ 675 – ₹ 350 = ₹ 325

(iv) Balance in the account = ₹ 325
Amount deposited = ₹ 89(+)
Amount left = ₹ 325 + ₹ 89 = ₹ 414

(v) Balance in the account = ₹ 414
Amount withdrawn = ₹ 300 (-)
Amount left = ₹ 414 – ₹ 300 = ₹ 114

Question 5.
A poet Tamizh Nambi lost 35 pages of his ‘lyrics’ when his file had got wet in the rain. Use integers, to determine the following.
(i) If Tamil Nambi wrote 5 pages per day, how many day’s work did he lose?
(ii) If four pages contained 1800 characters, (letters) how many characters were lost?
(iii) If Tamil Nambi is paid ₹ 250 for each page produced, how much money did he lose?
(iv) If Kavimaan helps Tamizh Nambi and they are able to produce 7 pages per day, how many days will it take to recreate the work lost?
(v) Tamizh Nambi pays Kavimann ₹ 100 per page for his help. How much money does Kavimaan receive?
Solution:
Total pages lost – 35
One day work = 5 page 35
35 pages = \(\frac{35}{5}\) = 7 days work
∴ 7 day’s work he lost.

(ii) Number of characters in four pages = 1800
Number of characters in one page = \(\frac{1800}{4}\) = 450
∴ Number of characters in 35 pages = 450 × 35 = 15,750 characters

(iii) Payment for one page = ₹ 250
∴ Payment for 35 pages = ₹ 250 × ₹ 35 = ₹ 8,750

(iv) Number of pages recreated a day = 7
∴ To recreate 35 pages day’s needed = \(\frac{35}{7}\) = 5 days

(v) Payment of Kavimaan = ₹ 100 per page
∴ for 35 pages payment = ₹ 100 × 35 = ₹ 3,500

Question 6.
Add 2 to me. Then multiply by 5 and subtract 10 and divide new by 4 and I will give you 15! Who am I?
Solution:
According to the problem {[(I + 2) × 5] – 10} ÷ 4 = 15
{[(I + 2) × 5] – 10} = 15 × 4 = 60
I + 2 = \(\frac{70}{5}\) = 14
(I + 2) × 5 = 60 + 10 = 70
I = 14 – 2 ; I = 12

Question 7.
Kamatchi, a fruit vendor sells 30 apples and 50 pomegranates. If she makes a profit of ? 8 per apple and loss ? 5 per pomegranate. What will be her overall profit or loss?
Solution:
Number of apples Kamatchi sold = 30
Profit per apple = ₹ 8(+)
∴ Profit for 30 apples = 30 × 8 = ₹ 240
Number of pomegranates sold 50
Loss per pomegranate = ₹ 5(-)
Loss on selling 50 pomegranates = 50 × (-5) = ₹ -250
Overall loss = -250 + 240 = ₹ -10
i.e. loss ₹ 10.

Question 8.
During a drought, the water level in a dam fell 3 inches per week for 6 consecutive weeks. What was the change in the water level in the dam at the end of this period?
Solution:
Water level fall per week = -3 inches
∴ Water level decrease for 6 weeks = 6 ₹ (-3) = 18 inches
∴ decrease of 18 inches of water level.

Question 9.
Buddha was born in 563 BC (BCE) and died in 483 BC (BCE). Was he alive in 500 BC (BCE)? and find his life time. (Source: Compton’s Encyclopedia)
Solution:
Years in BCC (BCE) are taken as negative integers.

Buddha was bom in -563
and died in -483
So he was alive in 500 BC (BCE)
Life time = -483 – (-563) = -483 + 563 = +80
Buddha’s life time = 80 years.

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 5 Geometry Ex 5.1

Question 1.
Name the pairs of adjacent angles.
Solution:
(i) ∠ABG and ∠GBC are adjacent angles.
(ii) ∠BCF and ∠FCD are adjacent angles.
(iii) ∠BCF and ∠FCE are adjacent angles.
(iv) ∠FCE and ∠ECD are adjacent angles.

Question 2.
Find the angle ∠JIL from the given figure.
Solution:
∠LIK and ∠KIJ are adjacent angles.
∴ ∠JIL = ∠LIK + ∠KIJ
= 38° + 27°
= 65°
∴ ∠JIL = 65°

Question 3.
Find the angles ∠GEH from the given figure.
Solution:

∠HEF = ∠HEG + ∠GEF
120° = ∠HEG + 34°
120°- 34° = ∠GEH + 34° – 34°
∠GEH = 86°

Question 4.
Given that AB is a straight line. Calculate the value of x° in the following cases.

Solution:
(i) Since the angles are linear pair ∠AOC + ∠BOC = 180°
72° + x° = 180°
72° + x° – 12° = 180°- 72°
x° = 108°

(ii) Since the angles are linear pair
∠AOC + ∠BOC = 180°
3x + 42° = 180°

(iii) Since the angles are linear pair
∠AOC + ∠BOC = 180°
4x° + 2x° = 180°
6x° = 180°
x° = 180°

Question 5.
One angle of a linear pair is a right angle. What can you say about the other angle?
Solution:
If the angle are linear pair, then their sum is 180°.
Given one angle is right angle ie 90°.
∴ The other angle = 180° -90° = 90°
∴ The other angle also a right angle

Question 6.
If the three angles at a point are in the ratio 1 : 4 : 7, find the value of each angle?
Solution:
We know that the sum of angles at a point is 360°.
Given the three angles are in the ratio 1:4:7.
Let the three angles be 1x, 4x, 7x.

∴ The three angles are 30°, 120° and 210°.

Question 7.
Three are six angles at a point. One of them is 45° and the other five angles are all equal. What is the measure of all the five angles.
Solution:
We know that the sum of angles at a point is 360°.
One angle = 45°
Let the equal angles be x° each
∴ x° + x° + x° + x° + x° + 45° = 360°
5x° + 45° – 45° = 360° – 45°

5x° = 315°

∴ Measure of all 5 equal angles = 63°.

Question 8.
In the given figure, identify
(i) Any two pairs of adjacent angles.
(ii) Two pairs of vertically opposite angles.
Solution:
(i) (a) ∠PQT and ∠TOS are adjacent angles.
(b) ∠PQU and ∠UQR are adjacent angles.
(ii) (a) ∠PQT and ∠RQU are vertically opposite angles.
(b) ∠TQR and ∠PQU are vertically opposite angles.

Question 9.
The angles at a point are x°, 2x°, 3x°, 4x° and 5x°. Find the value of the largest angle?
Sum of angles at a point = 360°
∴ x° + 2x° + 3x° + 4x° + 5x° = 360°
15x° = 360°
x° = \(\frac{360^{\circ}}{15}\)
x° = 24°.
∴ The largest angle = 5x°
= 5 × 24° = 120°
The largest angle is 120°

Question 10.
From the given figure, find the missing angle.
Solution:
Lines \(\overleftrightarrow { RP }\) and \(\overleftrightarrow { SQ }\) are interesting at ‘O’

∴ Vertically opposite angles are equal.
∴ x = 105°
∴ Missing angle = 105°

Question 11.
Find the angles x° and y° in the figure shown.

Solution:
Consider the line m.
x° and 3x° are linear pair of angles
∴ x° + 3x° = 180°


x° = 45°
Also lines l and m intersects.
Vertically opposite angles are equal.
ie 3x° = y°
3 × 45° = y°
y = 135°
x° = 15° and
y° = 135°

Question 12.
Using the figure, answer the following questions.

(i) What is the measure of angle x°?
(ii) What is the measure of angle y°?
Solution:
From the figure x° and 125° are vertically opposite angles. So they are equal ie
ie x° = 125°
Also y° and 125° are linear pair of angles.
∴ y° + 125° = 180°
y° + 125° – 125° = 180°- 125°
y° = 55°
x° = 125°,
y° = 55°

Question 13.
Adjective angles have
(i) No common interior, no common arm, no common vertex.
(ii) One common vertex, one common arm, common interior
(iii) One common arm, one common vertex, no common interior.
(iv) One common arm, no common vertex, no common interior.
Solution:
(iii) one common arm, one common vertex, no common interior

Question 14.
In the given figure the angles ∠1 and ∠2 are
(i) Opposite angles
(ii) Adjacent angles
(iii) Linear angles
(iv) Supplementary angles

Solution:
(iii) Linear pair

Question 15.
Vertically opposite angles are
(i) not equal in measure
(ii) Complementary
(iii) supplementary
(iv) equal in measure
Solution:
(iv) equal in measure

Question 16.
The sum of all angles at a point is
(i) 360°
(ii) 180°
(iii) 90°
(iv) 0°
Solution:
(i) 360°

Question 17.
The measure of ∠BOC is
(i) 90°
(ii) 180°
(iii) 80°
(iv) 100°

Solution:
(iii) 80°

You can Download Samacheer Kalvi 6th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 6th Maths Solutions Term 1 Chapter 5 Statistics Intext Questions

Recap (Textbook Page No. 108)

Question 1.
Count the objects in the following figure and complete the table that follows :

From Fig 5.1 and the table, answer the following question.
(i) The total number of objects in the above picture is ______
(ii) The difference between the number of squares and the number of bats is ______
(iii) The ratio of the number of balls to the number of bats is _______
(iv) What are the objects equal in number?
(v) How many more balls are there than the number of bats?
Solution:
(i) 24
(ii) 0
(iii) \(\frac{8}{6}=\frac{4}{3}\)
(iv) Bat and Square
(v) 2 balls more

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Tamilnadu Samacheer Kalvi 7th Maths Solutions Term 1 Chapter 6 Information Processing Ex 6.1

Question 1.
A tetromino is a shape obtained by …… squares together.
Solution:
4

Question 2.
Draw a tetromino which passes symmetry ……..
Solution:

Question 3.
Complete the table.

Solution:

Question 4.
Shade the figure completely, by using five tetrominoes shapes only once.

Solution:

Question 5.

Solution:

More possible ways are the

Question 6.
Match the tetrominoes of same type.

Solution:

Question 7.
Using the given tetrominoes with numbers, compute the 4 × 4 magic square.

Solution:

(more possible ways are these)