Here we will find examples from math that illustrate the various applications of Pi 

Area of a circle 

Archimede's method to calculating pi 

Pi = Circumference / Diameter

Story of Pi 

Pi

random numbers approximate Pi  

The wheel of angles

Daniel Mentrard

http://dmentrard.free.fr/GEOGEBRA/Maths/Export5/WheelofangleMD.html