In the figure, PQ is a tangent at a point R of the circle with centre O. If ∠TRQ = 30o.The measure of ∠PRS is
45o
120o
90o
60o
∠TRQ = 30o, ∠SRT = 90o (angle in a semi- circle)
∠TRQ + ∠SRT + ∠PRS = 180o => ∠PRS = 60o
An equilateral ABC is inscribed in a circle with centre O. Then measure of ∠BOC is