RD Chapter 10- Congruent Triangles Ex-10.2 |
RD Chapter 10- Congruent Triangles Ex-10.3 |
RD Chapter 10- Congruent Triangles Ex-10.4 |
RD Chapter 10- Congruent Triangles Ex-VSAQS |
RD Chapter 10- Congruent Triangles Ex-MCQS |

Write the complement of each of the following angles:

(i) 20°

(ii) 35°

(iii) 90°

(iv) 77°

(v) 30°

**Answer
1** :

We know that two angles are complement to each other if their sum is 90°. Therefore,

(i) Complement of 20° is (90° – 20°) = 70°

(ii) Complement of 35° is (90° – 35°) = 55°

(iii) Complement of 90° is (90° – 90°) = 0°

(iv) Complement of 77° is (90° – 77°) = 13°

(v) Complement of 30° is (90° – 30°) = 60°

Write the supplement of each of the following angles:

(i) 54°

(ii) 132°

(iii) 138°

**Answer
2** :

We know that two angles are supplement to each other if their sum if 180°. Therefore,

(i) Supplement of 54° is (180° – 54°) = 126°

(ii) Supplement of 132° is (180° – 132°) = 48°

(iii) Supplement of 138° is (180° – 138°) = 42°

**Answer
3** :

Let required angle = x, then

Its complement = x + 28°

∴ x + x + 28° = 90° ⇒ 2x = 90° – 28° = 62°

∴ x = = 31°

∴ Required angle = 31°

**Answer
4** :

Let the measure of the required angle = x

∴ Its complement = 90° – x

∴ x = (90° – x) + 30°

2x = 90° – x + 60°

⇒ 2x + x = 90° + 60°

⇒ 3x = 150°

⇒ x = = 50°

∴ Required angle = 50°

**Answer
5** :

Ratio in two supplementary angles = 4 : 5

Let first angle = 4x

Then second angle = 5x

∴ 4x + 5x = 180

⇒ 9x = 180°

∴ x == 20°

∴ First angle = 4x = 4 x 20° = 80°

and second angle = 5x

= 5 x 20° = 100°

**Answer
6** :

Let first angle = x ”

Then second angle = x + 48°

∴ x + x + 48° = 180°⇒ 2x + 48° = 180°

⇒ 2x = 180° – 48° = 132°

x= =66°

∴ First angle = 66°

and second angle = x + 48° = 66° + 48° = 114°

∴ Angles are 66°, 114°

**Answer
7** :

Let the required angle = x

Then its complement angle = 90° – x

∴ x = 8(90° – x)

⇒ x = 720° – 8x ⇒ x + 8x = 720°

⇒ 9x = 720° ⇒ x == 80°

∴ Required angle = 80°

**Answer
8** :

First complementary angle = (2x – 10°) and second = (x – 5)°

∴ 2x – 10° + x – 5° = 90°

⇒ 3x – 15° = 90° ⇒ 3x = 90° + 15° = 105°

∴ x == 35°

∴ First angle = 2x – 10° = 2 x 35° – 10°

= 70° – 10° = 60°

and second angle = x – 5 = 35° – 5 = 30°

**Answer
9** :

Let required angle = x°

Then its complement angle = 90° – x°

∴ x – (90° – x) = 10

⇒ x – 90° + x = 10°⇒ 2x = 10° + 90° = 100° 100°

⇒ x == 50°

∴ Required angle = 50°

**Answer
10** :

Let required angle = x

Then its supplement angle = 180° – x

∴ (180°-x)= x

540° – 3x = 2x ⇒ 2x + 3x = 540°

⇒ 5x = 540°⇒ x == 108°

-. Supplement angle = 180° – 108° = 72°

Name:

Email:

Copyright 2017, All Rights Reserved. A Product Design BY CoreNet Web Technology