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…

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 and was later …

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 …

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 …

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 …

Pi is an irrational number, meaning it cannot be expressed as a simple fraction and its decimal representation never ends or repeats. Pi has been calculated to over 100 trillion decimal places, …

Pi (π) (/ paɪ /) is a mathematical constant that is the ratio of a circle 's circumference to its diameter. This produces a number, and that number is always the same.

Pi (often represented by the lower-case Greek letter π), one of the most well-known mathematical constants, is the ratio of a circle’s circumference to its diameter.

The PI Behavioral Assessment is an untimed, free-choice, stimulus-response tool that measures a person’s motivating drives and needs. Try it for yourself.