Question

How to find circumference of circle.

Answer 1

Perimeter of circle

Given a circle of radius 'r'
$\therefore$ Perimeter = $2\pi r$
Now, we know, d = 2r
$\Rightarrow r=\frac{d}{2}$
$\therefore Perimeter=\frac{\text{/}2\pi .d}{\text{/}2}=\pi d$
$\therefore Perimeter=2\pi r=\pi d$