Description: Acute angles measure less than 90 degrees. Right angles measure 90 degrees. Obtuse angles measure more than 90 degrees. Learn about angles types and see examples of each. Created by Sal Khan. And the terminology I want to introduce you to are acute angles, right angles, and obtuse angles. An acute angle is an angle, well, let me just draw them first. So an acute angle will look something like that.*Teacher Advisor is 100% free.