Eli5: Why are circles specifically 360 degrees and not 100?
In: Mathematics
The ancient people who first figured out a lot of circle math did not use a base-10 number system like ours. They used a base-12 number system and counted the knuckles on their not-thumb fingers. 12 is a pretty nice number like 10. It divides evenly by 2 and 3. It was convenient for their math so that’s what they picked. (You can make a lot of arguments it’s more convenient than base-10, but base-10 is still pretty good and we’re real used to it.)
So they divided a circle into 360 degrees. They divided each degree into 60 “minutes”. They divided each “minute” into 60 “seconds”. They picked these numbers because 5 * 12 felt convenient to them I guess. Now you also sort of see how we ended up with our time-telling system: they divided that circle into 12 then reckoned why not keep the minutes/seconds divisions since it was convenient to have more divisions at smaller scales.
I think this was the Babylonians, I’m not sure. Either way, whichever people did it were the biggest empire at the time so they got to teach everybody how to do things. Eventually they fell, but people were used to using these systems and didn’t feel like changing them. How’d people end up with base-10 for other things? The *next* empire showed up with base-10, but didn’t have all of the geometry and other math the Babylonians did, so they just lifted it and kept it as-is because it’s stupid to rewrite an entire branch of math just to change the base, it’s smarter to just keep building on what’s there.
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