Best of the Web. Picked by our PhDs

This Bingo style game will help you memorize all those confusing polygon and basic geometry terms.

This is a nifty tool to help measure angles. The make-an-angle tool is really nice for teaching you how to use a protractor!

Help the robot destroy UFO’s with this silly little game that classifies angles as acute, obtuse, or right.

Use this matching game to practice classifying different types of triangles.

Explore the sum of the interior angles of polygons from triangles to octagons.

This dynamic paper is a great source for teachers and students. You can create geometric figures, nets, tesselations, number lines, grids, spinners, and graph paper and download it to your computer to print. A very neat tool!

Sort shapes into Venn diagrams according to their angles and sides.

Reflect, rotate, and translate different polygons using this tool.

This is a lesson plan for teachers or parents to use to teach similar figures. In this activity, you will blow up a cartoon character and draw it using grids.

Sort the pairs of shapes as congruent, similar, or neither.

This is a nice visual representation of the areas of rectangles, parallelograms, and triangles. It would be a nice addition to a teacher-led demonstration on area.

This tool allows students to discover the formulas for area of trapezoids, parallelograms, and triangles by changing their height and base.

See how area and circumference of a circle relate in this interactive lesson. This exploration has it all: guided teaching, student discovery, and practice problems!

Two visual representations of how to compute pi.

Which of these nets will form a cube?

Explore the relationship between the number of faces, edges, and vertices of various geometric solids using this tool.

Construct images of 3D figures using this nifty drawing tool.

A look at how the Pythagorean Theorem works. This is probably best as a teacher-led lesson.