Develop an understanding of the scale of similarity. Starting with the concept of congruency, the resource introduces the idea of similarity between two figures. As part of a larger playlist on geometry, it defines similarity and uses...

When the tape measure will not reach, use similarity. An installment of a large playlist on geometry introduces the method of indirect measurement. Using a story of finding the distance to the sun, the video shows how to use similar...

Two sets of congruent angles leads to three. Using diagrams of two triangles, the presentation intuitively shows that if two sets of angles are congruent, the third set is too. The portion of a geometry playlist uses that information to...

When given two sides and an angle, make similar triangles. The video describes the SAS Similarity Theorem. Using the theorem, the segment of a larger geometry playlist determines whether two triangles are similar.

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...

Examine similarity through a lens of transformations. A creative question asks learners to explain the properties of the angles and sides of similar figures. They must use the definition of transformations to build their explanations.

Show congruence in only two moves. Given the measures of sides and angles of two triangle, pupils determine the transformations needed to show the two triangles are congruent. Learners use a combination of a rotation and translation.

Find two similar triangles in plane sight. Given a figure composed of a parallelogram and a triangle, pupils identify two similar triangles and provide an explanation. Class members use the similar triangles to find two missing side...

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...

CPCTC (corresponding parts of congruent triangles are congruent) is COOL. Scholars look at a pair of congruent triangles. They use given measurements in the first triangle to find angle measures and sides of the second triangle.  

Can your class get around when the fair comes to town? Learners use the concepts of corresponding angles and proportions to find the distance between important stations at the county fair. Assess their progress and challenge...

Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...

How do you find the lengths of items that cannot be directly measured? The 13th installment in a series of 16 has pupils use the similarity content learned in an earlier resource to solve real-world problems. Class members determine...

Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...

Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...

Acute angle, line of symmetry, and vertex are a few terms you'll find in a set of 90 flashcards designed to reinforce math vocabulary. Included in the set are two types of cards; a word card printed in bold font, and a definition card...

Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...

How can you prove it? Guide classes through an exploration of two possible triangle congruence criteria: AAS and HL. Learners connect this criteria to those previous learned and also explore criteria that does not work. The lesson...

Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...

Looking for a strategy to organize the information related to transformations? The materials ask pupils to identify a sequence of rigid transformations, identify corresponding angles and sides, and write a congruence statement. They...

Corresponding parts, congruent parts, congruent corresponding parts—what does it all mean? The resource challenges pupils to identify corresponding parts for pairs of figures. It uses examples of figures that undergo rigid...