Why is it 360 degrees in a circle?
Why is it 360 degrees in a circle? Our FYI editor explains how the 360-degree circle came to be. The Mesopotamians passed their base-60 numerical system to the ancient Egyptians, who used it to divide a circle into 360 degrees. Therefore, six triangular slices of 60 degrees each made for a sensible 360-degree dissection of a circle. Why are there 2π radians in a whole turn? Note that whatever unit are used to measure r and s , in the definition of radian measure they cancel. They simply announce that once around the circle is 2π radians. (Some say 360∘...