To make circle other wise 180 d make a straight line or less than 360 d incomplete circle

The selection of 360 as the number of degrees (i.e., smallest practical sub-arcs) in a circle was probably based on the fact that 360 is approximately the number of days in a year. Its use is often said to originate from the methods of the ancient Babylonians. Ancient astronomers noticed that the stars in the sky, which circle the celestial pole every day, seem to advance in that circle by approximately one-360th of a circle, i.e., one degree, each day. (Ancient calendars, such as the Persian Calendar, used 360 days for a year.) Its application to measuring angles in geometry can possibly be traced to Thales who popularized geometry among the Greeks and lived in Anatolia (modern western Turkey) among people who had dealings with Egypt and Babylon.

Another motivation for choosing the number 360 is that it is readily divisible: 360 has 24 divisors (including 1 and 360), including every number from 1 to 10 except 7. For the number of degrees in a circle to be divisible by every number ...more

A circle has 360 degrees, but it also has 400 gradients and
approximately 6.2831853 radians. It all depends on what *units* you
measure your angles with.

Allow me to explain. Say you think 360 is a terrible number, and you
think that you want a circle to have 100 "somethings" in it. Well, you
divide up the circle into 100 equal angles, all coming out from the
center, and then you call one of these angles a "deeg." Then you've
just defined a new way to measure a circle. 100 deegs are in a circle.
...

The selection of 360 as the number of degrees (i.e., smallest practical sub-arcs) in a circle was probably based on the fact that 360 is approximately the number of days in a year. Its use is often said to originate from the methods of the ancient Babylonians. Ancient astronomers noticed that the stars in the sky, which circle the celestial pole every day, seem to advance in that circle by approximately one-360th of a circle, i.e., one degree, each day. (Ancient calendars, such as the Persian Calendar, used 360 days for a year.) Its application to measuring angles in geometry can possibly be traced to Thales who popularized geometry among the Greeks and lived in Anatolia (modern western Turkey) among people who had dealings with Egypt and Babylon.

Since it a combination of 4 right angles

A circle has 360 degrees, but it also has 400 gradients and
approximately 6.2831853 radians. It all depends on what *units* you
measure your angles with.

Allow me to explain. Say you think 360 is a terrible number, and you
think that you want a circle to have 100 "somethings" in it. Well, you
divide up the circle into 100 equal angles, all coming out from the
center, and then you call one of these angles a "deeg." Then you've
just defined a new way to measure a circle. 100 deegs are in a circle.
...more