Question

Calculate the area of a sector, length of whose arc is $20cm$ and radius is $7cm$.

Answer 1

Given, $r=7$ & $r\theta =20$

$\Rightarrow \theta =\frac{20}{7}$

Now, area of sector $=\frac{\theta }{2\pi }\times {\pi r}^2$

$=\frac{\theta }{2}{r}^2$

$=\frac{20}{14}\times 7\times 7$

$=70{cm}^2$