Pi is used to work out the geometry or circles and other round stuff. I don't know very much about all this, but it is a very interesting number. It's irrational, which means that it does not repeat itself, and seems to go on forever.
Pi starts off as 3.1415926... thats about as far as i can remember. This person in my year called Will can recite the first 60 something digits, but thats no where near a fration of the number. The fact is that the further you keep going, the more numbers you keep calculating. So far the first several billion digits have been calculated, but they keep calculating more. Well i think i have gone on about this long enough, so go check out all the stuff here.
