Information for Current Students

π is a mathematical constant and a transcendental (and therefore irrational) real number. It is the ratio of a circle's circumference to its diameter in Euclidean geometry, and has many uses in mathematics, physics, and engineering. While the value of π has been computed to billions of digits, practical science and engineering will rarely require more than 10 decimal places. As an example, computing the circumference of the Earth's equator from its radius using only 10 decimal places of π yields an error of less than 0.2 millimetres. The exact value of π has an infinite decimal expansion: its decimal expansion never ends and does not repeat, since π is an irrational number. More »