OCR C2 2011 January — Question 8

Exam BoardOCR
ModuleC2 (Core Mathematics 2)
Year2011
SessionJanuary
TopicRadians, Arc Length and Sector Area

8
\includegraphics[max width=\textwidth, alt={}, center]{c52fe7e9-0442-4b3e-b924-2e5e4b3e98f5-03_420_729_1027_708} The diagram shows a sector \(A O B\) of a circle with centre \(O\) and radius 5 cm . Angle \(A O B\) is \(\theta\) radians. The area of triangle \(A O B\) is \(8 \mathrm {~cm} ^ { 2 }\).
  1. Given that the angle \(\theta\) is obtuse, find \(\theta\). The shaded segment in the diagram is bounded by the chord \(A B\) and the arc \(A B\).
  2. Find the area of the segment, giving your answer correct to 3 significant figures.
  3. Find the perimeter of the segment, giving your answer correct to 3 significant figures.