This lesson focuses on polygons; a polygon is a closed, flat shape that has only straight sides. Polygons can have any number of sides and angles, but the sides cannot be curved.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to classify a polygon based on its sides and how to determine whether a polygon is convex or concave.

[Free Registration/Login may be required to access all resource tools.] Find interior angle measures of polygons by drawing diagonals to create triangles.

A comprehensive guide for learning all about concave shapes with definitions, the difference between concave and convex, examples, and practice questions.

Explore the structure and measurement of polygons.

This site provides definitions of different types of polygons and figures.

This in-depth paper examines the idea of convexity. Euclid's Elements, the first geometry textbook, assumed convexity without mentioning the term.

This website, from the University of Edinburgh, provides a lengthy glossary of computer graphics terms written by Olin Lathrop, author of "The Way Computer Graphics Work". This site provides simple definitions of basic terms; no graphics...