NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 5: Lines And Angles - Multiple Choice Questions

Question 33

Question.  33

In Fig. 5.27, a = 40°. The value of b is

(a)

(a) 20°

(b)

(b) 24°

(c)

(c) 36°

(d)

(d) 120°

Detailed Answer with Explanation:

Angles on a straight line: 2a + 5b = 180.

Substitute a=40: 80 + 5b = 180 ⇒ 5b=100 ⇒ b=20°.