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…

Dec 10, 2025 · 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 …

Draw a circle with a diameter (all the way across the circle) of 1. Then the circumference (all the way around the circle) is 3.14159265... a number known as Pi. Pi (pronounced like "pie") is often written …

The 1998 film Pi is a dark, strange, and hyperkinetic movie about a mathematician who is slowly going insane searching for a pattern to the Stock Market. Both a Hasidic cabalistic sect and a Wall Street …

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 …

In mathematical use, the lowercase letter π is distinguished from its capitalized and enlarged counterpart Π, which denotes a product of a sequence, analogously to how Σ denotes summation. The choice of …

It is defined as the ratio of a circle's circumference to its diameter, and it also has various equivalent definitions. It appears in many formulas in all areas of mathematics and physics. It is approximately …

The number Pi, denoted by the Greek letter π - pronounced 'pie', is one of the most common constants in all of mathematics. It is the circumference of any circle, divided by its diameter.

Learn about the mathematical definition, historical development, and practical applications of Pi (PI). Explore the decimal characteristics of π, digit distribution patterns, and its wide use in science, …