pi | Definition, Symbol, Number, & Facts
Pi, in mathematics, the ratio of the circumference of a circle to its diameter. The symbol π was devised by British mathematician William Jones in 1706 to represent the ratio and was later popularized by Swiss mathematician Leonhard Euler. Because pi is irrational (not equal to the ratio of any two whole numbers), its digits do not repeat, and an approximation such as 3.14 or 22/7 is often used for everyday calculations. To 39 decimal places, pi is 3.141592653589793238462643383279502884197. The Babylonians (c. 2000 bce) used 3.125 to approximate pi, a value they obtained by calculating the p...
Source: britannica.com
