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...
Math Open Reference
Math Open Reference: Polygons
Get the definition and properties of a polygon. Then explore such topics as: 1) types of polygon 2) area 3) Perimeter 4) angles associated with polygons and 5) names of polygons.
CK-12 Foundation
Ck 12: Geometry: Polygon Classification
[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.
Sophia Learning
Sophia: Classifying Polygons
This lesson explores the characteristics of various types of polygons. It includes two PowerPoint presentations that test students' understanding by grouping polygons in the correct categories.
ClassFlow
Class Flow: Polygons
[Free Registration/Login Required] This flipchart defines a polygon and the classification of concave and convex polygons.
National Council of Teachers of Mathematics
The Math Forum: Plane Figure
This site provides a definition for plane figure (at the top of the page) and a few examples.
University of Georgia
University of Georgia: Inter Math: Nonagon
This site gives the general definition of a nonagon with examples of a regular (convex) and irregular concave nonagons. There are links to related terms, challenging problems, more information, and the interactive check point involving...