Reason #1: The Length of the Year
The Earth takes one year to orbit the Sun. And a year is just a little more than 365 days. That means that the Earth rotates on its axis a little more than 365 times every year. And it means that every day the Sun appears to move about 1/365 of the way along a huge circle projected onto the sky that extends all the way around the Earth (called the ecliptic). If you lived a few millennia ago and didn’t have modern instruments to accurately record the positions of objects in the sky, you might conclude that the Sun moves about 1/360 of the way along this circle every day, which is exactly what ancient astronomers did. And they then made a leap and decided to divide this circle on the sky—and all circles—into 360 even parts so that the Sun would move through 1 part per day. Each of these parts was dubbed 1 degree, thus giving us the idea that a circle contains 360 degrees.
Makes sense, right? And given that the ancient Babylonian and Persian calendars were both based upon 360-day years, it seems likely that this simple astronomical observation is the reason a circle contains 360 degrees.
Join the telegram group: https://t.me/S2MATHEMATICSOFFICIAL
source
