Moderate -0.3 This is a straightforward two-step sector problem: use the area formula to find r, then calculate perimeter using arc length formula. Both formulas are standard recall items from C2, requiring only direct substitution and basic algebra with no problem-solving insight needed. Slightly easier than average due to its routine nature, though the 6 marks reflect the working required.
The diagram shows a sector \(OAB\) of a circle with centre \(O\) and radius \(r\) cm.
\includegraphics{figure_6}
The angle \(AOB\) is \(1.2\) radians. The area of the sector is \(33.75\) cm\(^2\).
Find the perimeter of the sector. [6]
The diagram shows a sector $OAB$ of a circle with centre $O$ and radius $r$ cm.
\includegraphics{figure_6}
The angle $AOB$ is $1.2$ radians. The area of the sector is $33.75$ cm$^2$.
Find the perimeter of the sector. [6]
\hfill \mbox{\textit{AQA C2 2009 Q6 [6]}}