4.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{8a7593c3-4f0b-4351-afae-7bd98cfc351d-06_513_775_269_589}
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\caption{Figure 1}
\end{figure}
Figure 1 shows a sketch of a design for a scraper blade. The blade \(A O B C D A\) consists of an isosceles triangle \(C O D\) joined along its equal sides to sectors \(O B C\) and \(O D A\) of a circle with centre \(O\) and radius 8 cm . Angles \(A O D\) and \(B O C\) are equal. \(A O B\) is a straight line and is parallel to the line \(D C . D C\) has length 7 cm .
- Show that the angle \(C O D\) is 0.906 radians, correct to 3 significant figures.
- Find the perimeter of \(A O B C D A\), giving your answer to 3 significant figures.
- Find the area of \(A O B C D A\), giving your answer to 3 significant figures.