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