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Pi
By Victora Eves on April 6, 1998:

HELP! I do not understand PI. I know that it works, I know the relevant formulas for circles, but I do not understand how someone came up with an idea that a number (p) could be used in
all circles for finding the area/circumference. please tell me how this number cam about and how it was proved to be true in all circles.

thank you
Victoria Eves

By Anonymous:

Dear Victoria,

You are absolutely right to feel as you do and in what you say because all GCSE mathematics really teaches about p are the relevant formulas for circles and that "it works", just as you say.

Mathematics has some amazing constants (like p and e) which crop up all over the place which is pretty awesome! But everything in maths can be proved, you don't have to take it on faith. To prove the circle formulas you need calculus which is done in A level maths.

There is a bit about the history and about Archimedes method for finding an approximate value for p in one of the answers to an earlier question on this web board, called Circumference of a Circle.

For thousands of years people have been trying to compute pi to more and more decimal places and now they are using very powerful computers to do this, rather pointless really!

Very best wishes,
NRICH