Question

The diameter of a circle is $10cm$. Find the length of the arc, if the corresponding central angle is ${180}^o$

Answer 1

Fact: Length of arc of a circle with radius $r$ making central angle $\theta$ is given by $\left(\frac{\theta }{{360}^o}\right)2\pi r$

Here $\theta ={180}^o$ and $r=10$ cm

So length of arc $=\frac{{180}^o}{{360}^o}\cdot 2\pi \left(10\right)=10\pi$ cm