NASA engineers use pi to calculate how far the rovers on Mars have travelled, for example.

Calculate Pi by throwing frozen Hot Dogs Calculating Pi is easy (just divide a circle’s circumference with its diameter) but there are also experimental ways to calculate it.

However, calculating pi to ever-increasing precision was already a pastime beloved of mathematicians. Isaac Newton spent many hours engrossed in calculating a 15-digit value for pi as a constant ...

The first example of a computer being to calculate Pi was in 1949, when John von Neumann and chums used ENIAC (Electronic Numerical Integrator And Computer) to compute 2,037 digits of Pi.

Outside the US, Pi Day should probably be July 22 (22/7)—this fraction is a surprisingly good estimate of pi. You can find the value of pi with a mass and a spring.