How to Solve for Radius in Excel. 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.

Use a ruler or measuring tape to measure your height from the bottom of your feet to the top of your head. Follow the instructions above for how to measure waist size using a measuring tape.

The circumference of a circle is its outside edge, and is the same distance from the centre at every point along its length. This distance is called the radius.