Happy Pi Day!1 To celebrate I want to get away from software for a bit and talk about something special. You may have heard the story that the Indiana legislature tried to change the value of π, to something like 3 or 4 or 3.15 or something like that. This is usually shared as evidence that Indianans Hoosiers are dumb hicks, but I don’t like leaving things at that. Why did they try to change π and what did they expect to happen?
I did the research, and now you get to hear the whole story. But to fully understand the context, I’ll need to explain math.
The Western math tradition starts with the Greeks. They weren’t the first civilization to do math, and many things attributed to them were discovered earlier by Babylonian, Egyptian, and Chinese mathematicians. But those discoveries come to us through Greek antiquity. They were also indisputably the best geometers of their time. The Greeks were especially interested in a class of problems known as “straight-edge and compass problems”.
Given an infinitely long edge with no markings and a circle-drawing compass, what shapes can you construct, and what can you get out of existing shapes? You can do a lot more than you’d expect! For example, you can take an angle and “bisect it”, or draw a line that splits it in exact halves. You can take a line and construct a 32-gon from it. You can take a square and construct another square with exactly twice the area.