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  1. One Million Digits of Pi On One Page!- [Plus Guides And ... - Pi Day

    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…

  2. Pi - Wikipedia

    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.

  3. Pi | Definition, Symbol, Number, History, Applications, & Facts ...

    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 …

  4. Pi - Math is Fun

    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 …

  5. What Is Pi, and How Did It Originate? - Scientific American

    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.

  6. Pi Symbol (π)

    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 …

  7. Pi (π) - Math Tools

    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 …

  8. Pi - Math.net

    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 …

  9. Explore Pi

    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, …

  10. PI - Math.com

    Pi is a name given to the ratio of the circumference of a circle to the diameter. That means, for any circle, you can divide the circumference (the distance around the circle) by the diameter and always …