Question 996948
Why angle around a circle is 360 degree??
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By definition.
A long time ago, people noticed that the Earth went around the sun in ~360 days.  A year was defined as 360 days for a while.
360 was an attractive number to them since it's divisible by several integers.  The religious people might have been involved, too, I'm not sure, thinking some god had designed it like that.
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It was later determined that a year on Earth is 365 days, 5 hours, 48 minutes and 46 seconds.
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A circle is also 400 grads, again by definition, for convenience.