7.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{ea81408b-e292-4529-b1e2-e3246503a3ac-09_440_437_285_772}
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\caption{Figure 1}
\end{figure}
Figure 1 shows a circle with centre \(O\) and radius 9 cm . The points \(A\) and \(B\) lie on the circumference of this circle. The minor sector \(O A B\) has perimeter 30 cm and the angle between the radii \(O A\) and \(O B\) of this sector is \(\theta\) radians.
Find
- the length of the arc \(A B\),
- the value of \(\theta\),
- the area of the minor sector \(O A B\),
- the area of triangle \(O A B\), giving your answer to 3 significant figures.