3.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{b5f50f17-9f1b-4b4c-baf3-e50de5f2ea9c-06_332_348_246_861}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{figure}
Figure 1 shows a sector \(A O B\) of a circle with centre \(O\) and radius \(r \mathrm {~cm}\).
The angle \(A O B\) is \(\theta\) radians.
The area of the sector \(A O B\) is \(11 \mathrm {~cm} ^ { 2 }\)
Given that the perimeter of the sector is 4 times the length of the arc \(A B\), find the exact value of \(r\).