This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons is broken...

The task at hand is to partition a hexagon into two, four, and eight congruent figures. Make sure to give your wizards a sheet of triangle grid paper on which to decompose the hexagons. Have them explain which rotations, reflections, or...

Here the focus is on triangle congruence. Through an activity that requires investigation, questioning, and working together, geometers learn to identify corresponding parts of triangles to determine if the triangles are congruent....

Continuing his SAT review session, Sal explores problems with slopes, linear equations, and congruent angles. He begins problem 10 (geometry) but finishes the problem in the next video.

Middle and high schoolers participate in a seven-part lesson creating Escher-Esque tessellations. They demonstrate their knowledge of geometric transformations after viewing a PowerPoint presentation, conducting Internet research, and...

Sal shows your students how to thoroughly and effectively read and solve math problems on the CAHSEE (and other standardized tests) in this engaging video. From masters of geometry to students who struggle with basic math skills, these...

All the 2-D and 3-D measurement work you need is in one location. Divided into three sections, the geometry lesson plans consist of visualization of three dimensions, classifying geometric figures, and finding surface area and volume....

Communication is the key. A dozen sample items require scholars to communicate their reasoning involved in arriving at a solution. The PowerPoint from the Gr. 8 Claim 2 - 4 Item Slide Shows series uses a variety of content to illicit...

Transform the thinking of transformations with six sample items that illustrate the first four standards in the eighth grade geometry domain. Items use the coordinate plane to transform figures and analyze the relationship of the figures...

Construct yourself a winning geometry unit. A set of lessons introduces geometry scholars to constructions and proofs with compasses and straightedges. It also covers triangle congruence through transformations. This is the second of...

Which is the best reflection of them all? Given four diagrams, pupils determine which one shows the most accurate reflection of a quadrilateral. Two images provide the distances of each vertex from the line of reflection, as well as the...

You don't want your bulletin board to be exactly the same as the others. Groups conduct an exploration to see what information is necessary to prove that triangles are congruent in the context of triangular designs on bulletin boards. As...

Lead by example. Pupils use software to investigate given measures of sides and angles to determine whether they create congruent triangles. Using the discovered triangle congruences, learners put together proofs.

Use the right congruence statement. The video introduces the Hypotenuse-Leg Theorem to prove two right triangles are congruent. Part of a geometry playlist shows that it does not matter which leg to use when proving congruence.

The location of the side makes a difference. One of the videos in a geometry playlist introduces angle-side-angle and angle-angle-side congruence relationships. Using drawings, the video shows how these two congruence statements are...

Gimme three sides, mister! The video introduces the Side-Side-Side Triangle Congruence Theorem. Using segments of different lengths, the portion of a larger playlist on geometry shows that only one triangle can be built.

If two sets of angles are equal, the third set is too. An informative portion of a playlist on geometry develops the Third Angle Theorem for triangles. Using the theorem, the presenter shows how to determine the measure of missing angles...

SAS is not just a spy organization. A section of an extensive geometry playlist introduces a way to show two triangles are congruent, SAS. Using diagrams, the video provides an explanation by showing only one triangle is formed with two...

Provide a large amount of information in a short statement. A segment of a playlist on basic geometry introduces the notation to denote congruence between two figures. The video shows how to read corresponding parts from a congruence...

Given two congruent triangles, the resource provides the definition of congruent triangles and marks the corresponding parts. The portion of a basic geometry playlist shows the triangles are congruent by moving one on top of the other...

How is congruence shown? Using angles, the resource introduces the congruence symbol and explains the meaning of being congruent. A segment of a larger playlist on basic geometry discusses bisection as a way to arrive at two congruent...