the wheel that they use has to have a circumference of one metre? And to make sure that’s accurate, we can multiply the diameter, which goes through the centre of the wheel, by the ratio of pi ...

Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr ...

Pi, or π, is the ratio of a circle's circumference to its diameter. Because it is irrational, it can't be written as a fraction. Instead, it is an infinitely long, nonrepeating number.

Talk about a pi pioneer! Pi (the Greek letter π, pronounced like the word "pie") is the ratio of the circumference of any circle to the diameter of that circle, explains math instructor Steven ...