Question

A area of a sector is 1540 sq cm , it subtends an angle of ${50}^{\circ }$ at the centre of the circle . Find the radius of the circle.

Answer 1

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

$\Rightarrow 1540=\frac{50}{360}\times \frac{22}{7}\times r^2$

$\Rightarrow r^2=\frac{1540\times 360\times 7}{50\times 22}=3528$

$\therefore r=59.4$cm