types of angles

An acute angle is an angle that is between 0 degrees and 90 degrees.

A right angle is an angle that is exactly 90 degrees. We use a square to indicate a right angle.

An obtuse angle is an angle that is between 90 degrees and 180 degrees.

A straight angle is an angle that is exactly 180 degrees. 

A reflex angle is an angle that is between 180 degrees and 360 degrees.