Flashcard 6 - Geometry Flashcard Set for the Math Basics

The circumference is the perimeter (distance around) the circle. The formula for finding it is:

\(C=\pi \cdot d\quad\) or \(\quad C= 2\pi r\)

If the diameter of a circle is 8 cm, then \(C=\pi \cdot 8 = 8 \pi \;cm\).
You can use \(3.14\) as an approximation for \(\pi\) and approximate the circumference: \(C \approx 25.12 \; cm\).

This is not to be confused with the formula for Area: \(A_\circ=\pi r^2\)