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Learn about pi, the ratio of the circumference of a circle to its diameter, and see the first million digits of its decimal expansion. You can also calculate the circumference of a circle using pi and check out our Pi Day merch.
- What Is Pi
Pi (often represented by the lower-case Greek letter π), one...
- What Is Pi
The number π (/ p aɪ /; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics.
Jun 25, 2024 · Pi is the ratio of the circumference of a circle to its diameter, and it is an irrational number with infinite decimal places. Learn about the history, calculation, and applications of pi in mathematics, physics, and engineering.
- The Editors of Encyclopaedia Britannica
- Pi is the ratio of the circumference of a circle to its diameter.
- The value of pi is approximately 3.14, or 22/7. To 39 decimal places, pi is 3.141592653589793238462643383279502884197. Pi is an irrational number,...
- The symbol for pi is π. It was devised by British mathematician William Jones in 1706 to represent the ratio and was later popularized by the Swiss...
- Pi is used for solving problems involving the lengths of arcs or other curves, the areas of ellipses, sectors, and other curved surfaces, and the v...
- Finding Pi Yourself. Draw a circle, or use something circular like a plate. Measure around the edge (the circumference): I got 82 cm. Measure across the circle (the diameter)
- Using Pi. We can use π to find a Circumference when we know the Diameter. Circumference = π × Diameter. Example: You walk around a circle which has a diameter of 100 m, how far have you walked?
- Radius. The radius is half of the diameter, so we can also say: For a circle with a radius of 1. The distance half way around the circle is π = 3.14159265...
- Digits. π is approximately equal to: 3.14159265358979323846… The digits go on and on with no pattern. π has been calculated to over 100 trillion decimal places and still there is no pattern to the digits, see Pi Normal.
Pi is the ratio of a circle's circumference to its diameter, and it is an irrational and transcendental number. Explore the history, properties, and applications of pi in mathematics and beyond.
Pi (π) is the ratio of the circumference of a circle to its diameter, an irrational number that can be approximated by 3.14. Learn how pi is used in geometry, trigonometry and other branches of mathematics, and see examples of formulas for circle, sphere, cylinder and cone.
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. Regardless of the circle's size, this ratio will...