How do you find circumference if you have radius?

Answer 1

First of all, let's define circumference.

Circumference is the diameter of a circle times pi (3.14)

So it would take 3.14 diameters to go around the circumference of a circle.

A radius is from the center of a circle to the outside. It is half the length of the diameter.

So, take the radius and double it. That will give you the diameter.

Take the diameter and multiply it by pi. Pi is the button on your scientific calculator that looks like Stonehenge.

If you do not have a pi button, 3.14 will give you a rough estimate.