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pi.md

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 # Pi
 
-Pi is one of the most important and famous [numbers](number.md), equal to approximately 3.14, most popularly defined as the ratio of a circle's circumference to its diameter (but also definable in other ways). It is one of the most fundamental mathematical constants of our universe and appears extremely commonly in [mathematics](math.md), nature and, of course, [programming](programming.md). When written down in traditional decimal system, its digits go on and on without end and show no repetition or simple pattern, appearing "random" and [chaotic](chaos.md) -- as of 2021 pi has been evaluated by [computers](computer.md) to 62831853071796 digits. In significance and properties pi is similar to another famous number: [e](e.md). Pi day is celebrated on March 14.
+Pi (normally written with a Greek alphabet symbol with [Unicode](unicode.md) value U+03C0) is one of the most important and famous [numbers](number.md), equal to approximately 3.14, most popularly defined as the ratio of a circle's circumference to its diameter (but also definable in other ways). It is one of the most fundamental mathematical constants of our universe and appears extremely commonly in [mathematics](math.md), nature and, of course, [programming](programming.md). When written down in traditional decimal system, its digits go on and on without end and show no repetition or simple pattern, appearing "random" and [chaotic](chaos.md) -- as of 2021 pi has been evaluated by [computers](computer.md) to 62831853071796 digits. In significance and properties pi is similar to another famous number: [e](e.md). Pi day is celebrated on March 14.
 
 { Very nice site about pi: http://www.pi314.net. ~drummyfish }