Question

From a circle with radius $21cm$ a sector is cut off for which the measure of the angle at the centre is $150$. Find the length of the arc of that sector and also find the area of the sector.

Answer 1

$r=21cm$

$\theta ={150}^o$

Length of arc $=2\pi r\times \frac{\theta }{360}$

$=2\times \frac{22}{7}\times 21\times \frac{150}{360}$

$=55cm$

Area of sector $=\pi r^2\times \frac{\theta }{360}$

$=\frac{22}{7}\times 21\times 21\times \frac{150}{360}$

$=577.5c{m}^2$