Degree measure of an Angle

Circles divides into 360 equal parts and the unit is one of the 360 parts, or   This unit is called degree, we usually use the sign(°). 

The drawing above shows a circle divided into 360 equal parts. The numerals label the marks 
for each of 10 arcs, beginning at 0. The arc from 0 to 1 is a 1-degree arc. 1° is read “one degree”. The arc from 0 to 10 is a 10-degree arc.  

The following illustrates the number of degrees in angles of standard rotations. 

Magnitude of An angle 
Magnitude of an angle is the amount of rotation through which one of the arms must be rotated about the vertex to bring it to the position of the other arm.