(a)[3]
Find $a$.
(b)[2]
Find an expression, in terms of $\pi$ and $r$, for the perimeter of the sector.
Mathematics 4024 · O Level · Circles, arcs and sectors
Circles, arcs and sectors — practice question
The diagram represents a sector of a circle with radius $3r\text{ cm}$ and angle $a\degree$, together with a circle of radius $r\text{ cm}$. The area ratio of the sector to the circle with radius $r$ cm is $8:1$.