CK-12 Foundation
Polygon Classification
Polly want a polygon? Young mathematicians sort shapes using an interactive. They classify the shapes as convex polygons, concave polygons, or not polygons.
Sophia Learning
Sophia: Sum of Angles in Polygons
This tutorial with video and slideshow components investigate the characteristics of polygons as well as how to calculate the interior and exterior angles of any polygon. It offers two PowerPoint presentations and two videos that feature...