Edexcel P1 2020 October — Question 3

Exam BoardEdexcel
ModuleP1 (Pure Mathematics 1)
Year2020
SessionOctober
TopicRadians, Arc Length and Sector Area

3. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{dfb4b2bc-4bc8-4e5b-9b13-ffe4fbde1b4f-08_885_1388_260_287} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} Figure 1 shows the design for a badge.
The design consists of two congruent triangles, \(A O C\) and \(B O C\), joined to a sector \(A O B\) of a circle centre \(O\).
  • Angle \(A O B = \alpha\)
  • \(A O = O B = 3 \mathrm {~cm}\)
  • \(O C = 5 \mathrm {~cm}\)
Given that the area of sector \(A O B\) is \(7.2 \mathrm {~cm} ^ { 2 }\)
  1. show that \(\alpha = 1.6\) radians.
  2. Hence find
    1. the area of the badge, giving your answer in \(\mathrm { cm } ^ { 2 }\) to 2 significant figures,
    2. the perimeter of the badge, giving your answer in cm to one decimal place.
      VIXV SIHIANI III IM IONOOVIAV SIHI NI JYHAM ION OOVI4V SIHI NI JLIYM ION OO