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 …

Hi, I'm Pi. I'm your personal AI, designed to be supportive, smart, and there for you anytime. Ask me for advice, for answers, or let's talk about whatever's on your mind.

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 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 …

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 …

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 …

The Pi Song (Memorize 100 Digits Of π) | SCIENCE SONGS AsapSCIENCE 10.8M subscribers Subscribe

Discover what pi means in math, why it’s written as π, how to use it for circles and spheres, and why it continues to amaze mathematicians.