You Can Approximate Pi by Dropping Needles on the Floor

"Pi is an infinitely long decimal number that never repeats. How do we know? Well, humans have calculated it to 314 trillion decimal places and didn't reach the end. At that point, I'm inclined to accept it. I mean, NASA uses only the first 15 decimal places for navigating spacecraft, and that's more than enough for earthly applications."

"The coolest thing, for me, is that there are many ways to approximate that value, which I've written about in the past. For instance, you can do it by oscillating a mass on a spring. But maybe the craziest method of all was proven in 1777 by George Louis Leclerc, Comte de Buffon."

"Imagine you have a floor with parallel lines separated by a distance d. Onto this floor, you drop a bunch of needles with length L. What is the probability that a needle will cross one of the parallel lines? This is not the most trivial problem, but let's think about just one dropped needle."

Pi is an irrational number representing the ratio of a circle's circumference to its diameter, appearing in diverse fields from music to quantum mechanics. Calculated to 314 trillion decimal places without repetition, pi's infinite nature is accepted despite NASA requiring only 15 decimal places for spacecraft navigation. Multiple approximation methods exist, including oscillating masses on springs. Buffon's needle problem, proven in 1777, offers a geometric probability approach: dropping needles onto a floor with parallel lines separated by distance d reveals pi through the probability that needles cross the lines, with results depending on needle length and angle relative to the lines.

Read at WIRED