Question

The diameter of circle is 20 inches. find the circumference in terms of pi

Answer 1

The below formula is used to find the circumference of a circle;

`C=2\pi r`

But we know that the diameter of a circle is expressed as;

`d=2r`

Let's replace 2r with d in the 1st equation, we'll then have;

`C=\pi d`

We've been told that the diameter of the circle is 20inches, if we substitute this value into our equation, we'll have;

`C=20\pi`