A Survey of Mathematics Related Topics: Pg. 216, "A Piece of the Pi"

This activity allows the user to run a simulation of dropping a needle on a lined sheet of paper and determining the probability of the needle crossing one of the lines. The remarkable result is that the probability is directly related to the value of Pi. By using calculus, one can prove that the probability of a hit is 2/Pi, where Pi is defined as the ratio of a circle's circumference to its diameter. To calculate Pi from the needle drops, the computer program finds experimental probability:

Experimental Probability = (total # of hits)/(# of drops)

On the other hand, we have (approximately):

Experimental Probability = 2/Pi

We can use this fact to conclude that:

2(total # of hits)/(# of drops) = Pi (approximately)