WAEC - Mathematics (2021 - No. 29)
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°
คำอธิบาย
Angle at the centre O is twice the angle at the circumference.
i.e O = 72° * 2 = 144°
∠OPS = 180 - 144 = 36°