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. It appears in many …

Maximize the fun you can have this Pi Day by checking out our Pi Day Merch. The first million digits of pi (π) are below. Why not calculate the circumference of a circle using pi here. Or …

Nov 17, 2025 · The value of pi is approximately 3.14, or 22/7. Pi is an irrational number, which means it is not equal to the ratio of any two whole numbers. This also means pi can be …

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 …

Jul 23, 2025 · We define the π as the ratio of the circumference to the diameter of a circle. It is a constant used widely in every branch of Science and Mathematics. What is Pi? Pi is a symbol …

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 …

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 …

How is Pi (π) Calculated exactly? Calculating Pi usually involves taking any circle and dividing its circumference by its diameter.

π π is the ratio between a circle's circumference and diameter. That is, circumference diameter = π diametercircumference = π. π π is a fundamental constant in mathematics, especially in …

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.