A Better Approximation to Pi
The constant pi is used in any maths involving circles, and pi to 13 decimal places is 3.1415926535897.
The general approximate value used in schools is 22/7, which is 3.142857142857142857.... with the digits 142857 repeating indefinitely.
However, there is a better approximation to pi.
355/113 = 3.14159292035398
which is accurate to 6 decimal places, very accurate for a relatively simple fraction.

by Ananth Balakrishnan

Go on facts for a more precise measurement of pi - it goes to about 400 decimal places.