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## Tamilnadu Samacheer Kalvi 6th Maths Solutions Term 1 Chapter 4 Geometry Ex 4.2

Question 1.

Use any number of the given dots to make different angles.

Solution:

Question 2.

Name the vertex and sides that form each angle.

Solution:

Question 3.

Pick out the Right angles from the given figures.

Solution:

(i), (iii) and (v) are Right Angles.

Question 4.

Pick out the Acute angles from the given figures.

Solution:

(i), (iii) and (iv) are the Acute Angles.

Question 5.

Pick out the Obtuse Angles from the given figures.

Solution:

(i) and (ii) are the Obtuse Angles.

Question 6.

Name the angle in each figure given below in all the possible ways.

Solution:

(i) ∠M or ∠LMN or ∠NML

(ii) ∠Q or ∠PQR or ∠RQP

(iii) ∠N or ∠MNO or ∠ONM

(iv) ∠A or ∠TAS or ∠SAT

(v) ∠Y or ∠XYZ or ∠ZYX

(vi) There are 3 angles in (vi)

- ∠ADC or ∠CDA
- ∠ CDB or ∠BDC
- ∠D or ∠ADB or ∠BDA

Question 7.

Say True or False.

- 20° and 70° are complementary.
- 88° and 12° are complementary.
- 80° and 180° are supplementary.
- 0° and 180° are supplementary.

Solution:

- True
- False
- False
- True

Question 8.

Draw and label each of the angles

(i) ∠NAS = 90°

(ii) ∠BLG = 35°

(iii) ∠SMC = 145°

Solution:

Question 9.

Identify the types of angles shown by the hands of the given clock.

Solution:

(i) Obtuse Angle.

(ii) Zero Angle.

(iii) Straight Angle.

(iv) Acute Angle.

(v) Right Angle.

Question 10.

Find the supplementary ‘l’ complementary angles in each case.

Solution:

(i) If two angles add up to 180°, they are supplementary.

We know that the straight angle ∠CBC = 180°

Given ∠CBD = 25°

∴ ∠DBA = 180° – 25° = 155°

∴ Supplementary ∠DBA = 155°

(ii) If two angles add upto 90°, they are complementary

Given ∠ABC = 25°

∠CBD = 30°

∴ ∠DBA = 90° – 30° = 60°

∴ Complementary angle ∠DBA = 60°

(iii) Given ∠CBA = 90°

∠CBD = 46°

∴ ∠DBA = 90° – 46° = 44°

We know that the sum of two angles is 90°, then they are complementary

∴ Complementary angle ∠DBA = 44°

(iv) Given ∠DBE = 180°

∠DBC = 67°

∴ ∠CBE = 180° – 67° = 113°

Here ∠DBC + ∠DBE = 180°

∴ Supplementary angle ∠CBE = 113°

**Objective Type Questions**

Question 11.

In this Figure, which is not the correct way of naming an angle?

(a) ∠Y

(b) ∠ZXY

(c) ∠ZYX

(d) ∠XYZ

Solution:

(b) ∠ZXY

Question 12.

In this Figure, ∠AYZ = 45°. If the point ‘A’ is shifted to point ‘B’ along the ray, then the measure of ∠BYZ is ____

(a) more than 45°

(b) 45°

(c) less than 45°

(d) 90°

Solution:

(b) 45°

Hint: ∠XYZ = ∠BYZ = ∠AYZ