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

An illustrated tutorial which takes students step-by-step through the process of drawing ray diagrams.

This site provides a basic experiment that shows how a lens works. This lesson plan explains nearsightedness and farsightedness. It also explains concave and convex lenses.

An experiment using Jell-O to create lenses, to see how light behaves with flat, concave, and convex lens surfaces. With an explanation of what is observed, and a link to an informative article on lenses.

This lesson explains what lenses are, the different between a converging and diverging lens, the difference between a double convex and double concave lens, and gives definitions for terms related to lenses.

Hotmath provides 21 practice problems dealing with systems of equations and inequalities. Each of the practice problems include a step-by-step guide for solving their algebraic problem.

This is an informative site from Georgia State University. It gives a discussion of the thin lens equation and an illustration of its use in determining the image distance based upon the object distance and the focal length.

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.

Introduces the concept of polyhedrons by learning the definition, types, and where they are found. Check-out the solved examples for better understanding and try your hand at solving a few interactive questions at the end of the page.

Provides a discussion of curved mirrors and ray diagrams. Shows and explains the process of drawing a ray diagram to determine the image location, size, and orientation.

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...

[Free Registration/Login Required] This flipchart defines a polygon and the classification of concave and convex polygons.

[Free Registration/Login Required] This flipchart reviews the characteristics of light and its properties. Students are given examples of reflection, refraction, and lens types. An assessment component is included.

This website, although mostly for selling artwork prints by M.C. Escher, provides a good picture of Escher's famous piece lithograph, "Convex and Concave." Includes some informative text.

This activity will allow students to use Cabri Jr. to find the sum of the measures of interior angles of convex polygons and visually see how the Interior Angle Sum Theorem works.

Learn how to construct convex polygons and the mathematical foundations of symmetry on this site.

Students discover properties of interior and exterior angles of convex polygons using the TI-89 and Geometer's Sketchpad.

[Free Registration/Login may be required to access all resource tools.] This study guide focuses on polygons: convex vs concave, interior and exterior angles, and basic terminology for common polygons.

Lenses are precisely shaped pieces of glass that have been developed and used in corrective glasses, telescopes, microscopes, binoculars, and magnifying glasses. They can be convex or concave. Links are provided to a video an a test.

Understand how lens curvature, focal length and f-stop are related.

There is exactly one reflection and no rotation that sends the convex quadrilateral ABCD onto itself. What shape(s) could quadrilateral ABCD be? Explain. Aligns with G-CO.A.3.

[Free Registration/Login Required] Learn about the type, size, location, and orientation of the image that forms when a thin lens is used to view an object using this interactive simulation. A PDF worksheet and a video tutorial are also...

A complete reference guide to irregular polygons. It provides definitions and an interactive activity that enhances further explanation. Includes links to related topics.

A complete reference guide to regular polygons. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.