(a)[3]
The shaded region has perimeter $(a\pi + b)\,\text{cm}$. Find the value of $a$ and the value of $b$.
(b)[3]
Calculate the area of the shaded region, and give your answer in its simplest form in terms of $\pi$.
Mathematics 4024 · O Level · Circles, arcs and sectors
Circles, arcs and sectors — practice question
The sectors OAB and OCD are parts of circles that each have centre $O$ and an angle of $60^{\circ}$. The radius of sector OAB is $6\,\text{cm}$. The radius of sector OCD is $9\,\text{cm}$.