Question

In a circle an arc subtends an angle ${45}^o$ at the centre. If the length of arc is $11cm$ then find the radius of circle.

Answer 1

Given: Length of arc $11cm$
The subtended angle by arc at the centre of circle $={45}^o$.
$\frac{2\pi r}{360}=$ Length of arc
$\Rightarrow \frac{2\times \frac{22}{7}\times r\times {45}^o}{360}=11$
$\Rightarrow r=\frac{11\times {360}^o\times 7}{2\times 22\times {45}^o}$
$r=14cm$
$\therefore$ Radius of circle $=14cm$.