AP State Syllabus AP Board 7th Class Maths Solutions Chapter 4 Lines and Angles Ex 3 Textbook Questions and Answers.

## AP State Syllabus 7th Class Maths Solutions 4th Lesson Lines and Angles Exercise 3

Question 1.

Which of the following pairs of angles are supplementary?

Solution:

i) Sum of the angles = 110° + 70° =180°

Hence they are supplementary.

ii) Sum of the angles = 90° + 90° =180°

hence they are supplementary.

iii) Sum of the angles = 50°+ 140° =190° ≠ 180°

Hence they are not supplementary.

Question 2.

Find the supplementary angles of the given angles.

(i) 105° (ii) 95° (iii) 150° (iv) 20°

Solution:

(i) 105°

Supplementary angle of 105° = 180° – 105° = 75°

(ii) 95°

Supplementary angle of 95° = 180° – 95° = 85

(iii) 150°

Supplementary angle of 150° = 180° – 150° = 30°

(iv) 20°

Supplementary angle of 20° = 20° = 180° – 20° = 60°

Question 3.

Two acute angles cannot form a pair of supplementary angles. Justify.

Solution:

As the measure of an acute angle is less than 90°, sum of two acute angles < 90° + 90° = 180°

Hence two acute angles cant brin a pair of supplementary angles.

Question 4.

Two angles are equal and supplementary to each other. Find them.

Solution:

Let the angle be x°

then its supplementary 180° – x°

By problem, x° =180° – x°

x° + x° = 180°

x° = \(\frac{180^{\circ}}{2}\)

x° = 90°