What is a diameter formula as a function of circumference?

The diameter of a circle can be expressed as a function of its circumference using the formula ( d = \frac{C}{\pi} ), where ( d ) is the diameter and ( C ) is the circumference. This relationship arises from the definition of the circumference, which is ( C = \pi d ). Thus, by rearranging the formula, you can easily find the diameter if the circumference is known.