Revision as of 07:39, 24 June 2006 by Cosinator (talk | contribs) (Symbol for pi)


Pi is an irrational number denoted by the greek letter $\displaystyle \pi$. It is the ratio of a circle's circumference, or perimeter, to its diameter. It is roughly equal to 3.141592653. The number pi is usually only useful when dealing with circles, spheres, and discs. The fractional approximation for pi (not exact) can be $\frac{22}{7}$. The exact formula for pi is $4\left( \sum_{i = 0}^\infty (-1)^i \left(\frac{1}{2n+1}\right)\right)$

See Also

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