3 (a) AC is a diameter of the circle, centre O. BCD and OED are straight lines. AC = 6 cm and CD = 3 cm. BACˆ = 34°. (i) Explain why BCAˆ = 56°. (ii) Find CODˆ. (iii) Find OCEˆ. (b) In the diagram, PS is the bisector of QPRˆ. QPT and QSR are straight lines. RT is parallel to SP. (i) Explain why PT = PR. (ii) This diagram shows part of the above diagram. PQ = 12 cm, PR = 5 cm and QR = 8.5 cm. It is given that PQ/PR =QS/SR . Find SR.