Question

Find the angle subtended at the centre of a circle of radius 5 cm by an arc of length $\left(\frac{5\pi }{3}\right)cm$

Answer 1

We know that the arc length $l$ of a sector of an angle $\theta$ in a circle of radius $r$ is

$l=\frac{\theta }{{360}^o}\times 2\pi r$

$\Rightarrow \frac{5\pi }{3}=\frac{\theta }{{360}^o}\times 2\pi \times 5$

$\therefore \theta ={60}^o$