The number π (/ paɪ / ⓘ; spelled out as pi) is a mathematical constant, approximately equal to 3.14159, that is the ratio of a circle 's circumference to its diameter.

The first million digits of pi (π) are below. Why not calculate the circumference of a circle using pi here. Or simply learn about pi here. Maximize the fun you…

Mar 2, 2026 · pi (π), in mathematics, the ratio of the circumference of a circle to its diameter. The Greek letter π was first used by British mathematician William Jones in 1706 to represent the ratio …

Then the circumference (all the way around the circle) is 3.14159265... a number known as Pi. Pi (pronounced like "pie") is often written using the Greek symbol π. With a diameter of D the …

100,000 Digits of Pi 3.141592653589793238462643383279502884197169399375105820974944592307816406286 ...

The Greek small letter π (pi) is used in trigonometry as a constant to represent a half-rotation around a circle in radians. The value of π is approximately 3.14159 and appears in many math formulas and …

May 17, 1999 · Succinctly, pi—which is written as the Greek letter for p, or π—is the ratio of the circumference of any circle to the diameter of that circle.

Pi is a constant value. That is, the ratio of the circumference to the diameter is the same for all circles. The drawing below shows the circumference of a circle that has been "straightened out." It is a little …

Learn about the Greek letter Pi (π), its pronunciation, usage examples, and common applications in mathematics, science, and engineering.

Mar 13, 2023 · Greek mathematician Archimedes of Syracuse calculated the infinite mathematical concept pi in the 200s BCE, which we celebrate annually on March 14, or Pi Day.