Question 9

Give reasons for your statements and calculations in QUESTIONS 9, 10, 11 and 12.

9.1 In the diagram below, O is the centre of the circle and point T lies on chord RS. Prove the theorem which states that if OT ⊥ RTS then RT = TS.

(5)

9.2 In the diagram, O is the centre of circle ABD. F is a point on chord AB such that DOF ⊥ AB. AB = FD = 8 cm and OF = x cm.

Determine the length of the radius of the circle. (5)

[10]