Question

The diameter of a circle is 9cm. Find its circumference in terms of pi

Answer 1

`9\pi`

Explanation:

To find circumference you need to use the formula
`2\pi r= C` or
`d\pi =c`. We don't have the radius, but we do have the diameter so we have to use the second formula.

The diameter is 9 so we insert it into the formula.

`d\pi=C\\\\9\pi=C\\\\`

So the circumference is
`9\pi`