This lesson focuses on acute, obtuse, and reflex angles, and the sum of the interior angles of polygons. Students begin by naming and visually estimating angle measures. They then compare angle measures and use multiples of 45° and 60° angles to build polygons. Students conclude the lesson by applying the sum of the interior angle measures of a quadrilateral and then the sum of angle measures of a polygon to find unknown angle measures.

Originally released by Learnetic, 2016.