Pi

about 3,141592653589793238462...


A so-called transcendent number, like the base of the natural logarithms (e=2,71828...). Transcendent numbers have infinite decimal places and can't be described exactly by a fraction. Though note that there are various algorithms for computing a particular digit without knowledge of the previous ones.


Pi is defined as the ratio of the circumference to the diameter for a circle (see 'Angles').


Pi - an easy-to-remember approximation:


1) Write down

1 1 3 3 5 5


2) Put a long division sign in the middle

1 1 3 / 3 5 5 ( i.e. 355/113)


3) Calculate it:

3 . 1 4 1 5 9 2 9 2 0 3 5

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