NCERT Class 9 Solutions: Line and Angles (Chapter 6) Exercise 6.1 – Part 2
Q3 In the figure, , then prove that
Solution:

In figure give point of P,Q,R,S,T and
To prove,

Equation,

(Linear Pair)
…………equation (1)

also,
(Linear Pair)
⇒
⇒ ………..equation (2)

From (i) and (ii)

Therefore,
Q4 In the figure, if , then prove that AOB is a line.
Given, point of A,B,C,D and angle of w, x, y, z
To Prove,AOB is a line (linear pair.)
Equation, (Angles around a point.)
Hence, makes a linear pair. Therefore, AOB is a staright line.