A right angle has 90 degrees. Angles are measured on a scale from 0 to 360 degrees. Right angles represent one-fourth of a full 360-degree revolution.

Right angles have their own symbol, which is a square in the corner where the two lines of the angle meet. Math has six kinds of angles: acute, right, obtuse, straight, reflex and full. Acute and obtuse angles are defined in relation to right angles, as acute angles are less than 90 degrees and obtuse angles are between 90 and 180 degrees. A straight angle is exactly 180 degrees, and a full angle is exactly 360 degrees. Reflex angles fall between 180 and 360 degrees.