New ReviewWhich 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...

What properties of equality also work for congruence? Part of basic geometry playlist, the video relates algebraic properties to their counterparts of congruence. Learners see how the properties mean the same whether with equality or...

Flip, turn, and slide to get there. With the aid of hands-on materials, pairs transform a figure from one place on the coordinate plane to another. They determine a sequence that will move one figure to another and present different...

Beware of the construction zone and watch for duplicating line segments and angles. The lesson plan leads pupils through the construction of congruent of line segments and angles. Class members follow the teacher's directions and then...

Prove it—triangles aren't congruent unless you prove them to be congruent. High school mathematicians learn to prove triangle congruence by using transformations. They see how rigid motions result in congruent sides and angles.

Applying their knowledge of theorems about lines, angles, and triangles, groups build a toothpick and stick bridge to support their text book. The teams use the design process to plan, build, test, and refine their bridge designs. The...

Assess your class' knowledge of triangle properties. Scholars interpret given information to determine how to find the measure of an unknown angle. The resource provides all information in the directions with the expectation that...

See how parallelograms can produce congruent triangles. Given a diagram of a parallelogram, scholars must show that two triangles are congruent. The triangles are made from the diagonals of the parallelogram.

Do transformations always result in congruent figures? Using a given pre-image triangle, scholars perform two separate transformations on the triangle. Based on the images, they decide whether the triangles are congruent.

Transform proofs using triangle rotations. By rotating a triangle around various points, class members develop proofs. Participants prove relationships of alternative interior angles formed by parallel lines and the sum of the interior...

Congruence, similarity, and alikeness are ways to describe relationships between figures. While congruence and similarity are common geometric terms, the writer coins the term alikeness to include one-dimensional stretch transformations....

Coordinate using transformation in congruence proofs. An assessment provides pupils with two triangles on the coordinate plane. Relying on known information about rigid transformations, scholars describe the transformations necessary to...

Transform triangles to show congruence. Given two triangles with congruent corresponding parts, pupils describe the rigid transformations that will show the two triangles are congruent, and then determine the sequence of transformations...

Translate, reflect, and rotate one triangle onto another. Given two triangles with corresponding parts, individuals use properties of rigid transformations to show the two triangles are congruent. Pupils show that after a series of...