Explanation:
In Mathematics, the circumference of any shape defines the path or the boundary that surrounds the shape. In other words, the circumference is also called the perimeter, which helps to identify the length of the outline of any shape. Recall that the definition of pi (π) is the circumference, c of any circle divided by its diameter, d. Put as an equation, pi is defined as
Rearranging this to solve for c we get
The diameter of a circle is twice its radius, so substituting 2r for d
