In the figure, O is the centre of the circle and ∠POR = 120°. Find ∠PQR and ∠PSR

Given, ∠POR = 120°

We know that “Angle subtended at the center is twice the angle subtended at circumference by the same chord”.

∠PQR =

⇒∠PQR =

⇒∠PQR = 60

Now, PQRS is a quadrilateral and angles on the opposite sides in the quadrilateral are supplementary.

∠ PSR = 180-∠ PQR

⇒∠ PSR = 180-60

⇒∠ PSR = 120^o