Protractors

You probably know that there are 360 degrees in a circle. But do you know why? It goes back about 4000 years ago. We inherited this number from the ancient Babylonians. They viewed the seasons as “circular,” and represented changes in a year around a circle. Though there are 365 days in a year, they wanted a number that is easier to work with. They also had a fancy for the number 60, and that is where we get 60 minutes in an hour. We also get 24 hours in a day from the ancient Babylonians.

A protractor is a device for measuring angles. Most protractors are semicircles so they contain 180 degrees, like this:

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