– π (pi) is a mathematical constant, approximately equal to 3.14159 If we know the circumference of a circle, we can easily find out its radius by rearranging this formula and solving for ‘r’: r = C / ...

The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...