Question

How can I find the circumference of a circle with only the diameter given?

Answer 1

This is the formula C=π⋅d. It just purely multiplication.

Answer 2

The circumference of a circle is equal to pi times the diameter.

C=πd

The diameter is two times the radius, so the equation for the circumference of a circle using the radius is two times pi times the radius.

C=2πr