In the given figure, calculate the value of angle q

In the given figure, calculate the value of angle q.
image

Since, AB is a straight line.
So,∠AOP + ∠POC + ∠COB = 180°
So, 50°+ x + 90° =180°
[∵ ∠AOP = 50° vertically opposite angles]
=» x +140° = 180°
=» x = 180°-140° = 40°
∵ q = x = 40° [vertically opposite angles]