JAMB 2012 · UTME · Q29

A circular arc subtends an angle of $150^\circ$ at the centre of a circle of radius $12\text{ cm}$ . Calculate the area of the sector.

Worked solution (try it first)

Area of a sector $= \frac{\theta}{360} \times \pi r^2$ , with $\frac{150}{360} = \frac{5}{12}$ and $r^2 = 144$ .
So the area is $\frac{5}{12} \times 144\pi = 60\pi\text{ cm}^2$ , option B.