In earlier lessons, students reasoned about angle measurements, learned to use a protractor, and measured given angles. They have sketched angles by referring to clock faces and sketched estimates of angles of a given size, based on benchmark angles.

In this lesson, students use a protractor to draw angles of specified measurements (not limited to benchmark angles) and to verify the sizes of the angles in their partners’ drawings. They begin to use known angle measurements to reason about unknown measurements and notice relationships between the measurements of angles that share the same starting endpoint.