March 15, 2013
Yesterday was pi day, so today we will estimate pi by a method that dates to 1777: if you randomly drop needles onto a flat surface with lines separated by the length of a needle, then the number of needles dropped, divided by the number of needles that intersect a line, will equal pi. You can determine if a needle intersects a line with a little bit of trigonometry. The method is called Buffon’s needle because it was discovered by the French naturalist Georges-Louis Leclerc, the Comte de Buffon. We did a similar exercise to this one a few years ago.
Your task is to write a program that calculates an approximate value of pi by simulating the dropping of a million needles. When you are finished, you are welcome to read or run a suggested solution, or to post your own solution or discuss the exercise in the comments below.