Learn about the definition of pi in relation to a circle with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

How do you find the area of a circle? Can you measure the area of a circle and use that to find a value for Pi?

I am Pi, the ratio of the circumference of a circle to its diameter. Picking up the phone here at the Smithsonian, I set out to find out more about Pi and how it is represented in the national ...

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.

The mathematical constant, which is the ratio of a circle’s circumference to its diameter, can be used to find the area or circumference of a circle -- or of that pie you’re hopefully enjoying ...