NCERT Class 9 Math Chapter 6 Exercise 6.1 covers lines and angles, including basic concepts and features of angles formed by parallel and transversal lines. The exercise introduces key terminologies like different interior angles, matching angles, co-interior angles, and vertically opposing angles. The activity consists of 15 questions to assess the students’ understanding and application of these concepts.
NCERT CLASS 9 Mathematics Chapter 6
Page No. 97
Exercise 6.1
Question No. 4
We know that the sum of angles around a point is 360°. Therefore x + y + w + z = 360°
⇒ (x + y) + (w + z) = 360°
⇒ (x + y) + (w + z) =360°
⇒ 2(x + y) = 360°
⇒ (x + y) = 360°/2
⇒ x + y = 180°
∠AOC and ∠COB are forming linear pair. Hence, AOB is a straight line.