Pie is equal to a baked dessert commonly made with fruits, and is quite tasty, if I do say so myself. :p
Pi, which I believe you were referring to, is a number that is approx. 3.1416, and is commonly used in trigonometry. Since it is a nonradical number, I highly doubt that you'd like me to type the entirety of pi, as I'd likely be stuck here forever, upon which you'd never get your answer. But, anyways, you could isolate pi from a number of formulas to isolate it and get an equation upon which you can solve for pi, such as pi = circumference / diameter. Hence, if you had an exact circumference and diameter, you'd likely be able to compute pi, but good luck with that. Pi is also equal to half of tau, which can be used in place of formulae such as C = 2 * pi * r, upon which this can be simplified to C = tau * r.
All-in-all, though, I prefer the first definition I posted