9709 P11 - Jun 2022 - Q5 - 7 marks
191
The diagram shows a sector ABC of a circle with centre A and radius \(r\). The line BD is perpendicular to AC. Angle CAB is \(\theta\) radians.
(a) Given that \(\theta=\pi/6\), find the exact area of BCD in terms of \(r\). [3]
(b) Given instead that the length of BD is \(\frac{\sqrt3}{2}r\), find the exact perimeter of BCD in terms of \(r\). [4]
