The circumference of a circle is the length of its perimiter. Since circles are difficult shapes measure (unlike rectangles and triangles), there is a slightly less obvious formula for finding their perimiter. The formula for calculating the circumference of a circle is the following: $$ C = 2\pi r $$ Where \(r\) is the radius of the circle and \(\pi\) is the mathematical constant pi. If you are not familiar with the \(\pi\) (pi) symbol, please visit this page: What is Pi?
