In the diagram, O is the centre of the circle PQRS, ∠PQR = 72° and OR is parallel to PS. Find ∠ OPS.
- 18°
- 108°
- 54°
-
36°
The correct answer is: D
Explanation
Angle at the centre O is twice the angle at the circumference.
i.e O = 72° * 2 = 144°
∠OPS = 180 - 144 = 36°