Virginia Department of Education
Congruent Triangles
Is this enough to show the two triangles are congruent? Small groups work through different combinations of constructing triangles from congruent parts to determine which combinations create only congruent triangles. Participants use the...
Curated OER
Congruent Triangles
Learners explore the concept of congruent triangles. In this congruent triangles lesson, students use Cabri Jr. to construct two congruent triangles using circles. Learners determine if the two triangles are congruent by using the SSS,...
Curated OER
Congruent Triangles Postulates
Students discover three lettered postulates that prove triangles congruent.
Curated OER
Congruent Triangles
Tenth graders explore congruent triangles. In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles are congruent by SSS, ASA, AAS, or SAS.Â
Curated OER
Congruent Trianges - Is This Enough Information?
Seventh graders determine whether two triangles are congruent and provide an explanation to why they are not. They apply concepts of measurement of angles and collect evidence of congruent angles in the world.
EngageNY
Triangle Congruency Proofs (part 1)
Can they put it all together? Ninth graders apply what they know about proofs and triangle congruence to complete these proofs. These proofs go beyond the basic triangle congruence proofs and use various properties, theorems, and...
Virginia Department of Education
Similar Triangles
Pupils work in pairs to investigate what it takes to prove that two triangles are similar. They work through various shortcuts to find which are enough to show a similarity relationship between the triangles. Small groups work with the...
West Contra Costa Unified School District
Investigating Similar Triangles
Let your use of the resource be in proportion to its usefulness. Pupils investigate similar triangles by measuring side lengths and considering given angle measures. The results of the investigation help develop generalizations about...
Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel lines cut...
Curated OER
Building Congruent Triangles
Students differentiate between congruent and similar triangles. In this geometry lesson, students identify the lengths and angle measures of triangles. They use postulates to prove their answers.
Curated OER
Similarity and Congruence
Students determine that two figures are similar or congruent by
investigating figures that are similar and figures that are congruent. They prove that two figures are similar or congruent by using definitions,
postulates, and theorems.
Curated OER
Congruent Triangles - Is This Enough Information?
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
Curated OER
The Truth About Triangles And Proofs
Students engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
Curated OER
Why can't We Use SSA to Prove Triangles Congruent?
Students investigate triangles and congruences. In this geometry lesson, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
Curated OER
Similarity and Congruence
Students explore the concept of similarity and congruence. In this similarity and congruence lesson, students cut out strips of paper and form a triangle. Students try to prove that their triangles are congruent using the SSS theorem of...
Curated OER
Similar Triangles
Ninth graders find the height of every day objects using techniques learned through postulates that allow triangles in a problem to be similar. They calculate the length of a missing side and solve proportions.
Curated OER
CSI Investigation of Congruence and Similarity
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
Curated OER
NON-EUCLIDEAN GEOMETRY.
Students study relationships between angles, side lengths, perimeters, areas and volumes of similar objects. In this lesson students also create and critique inductive and deductive arguments concerning congruency, similarity and the...
Curated OER
Geometry Jeopardy
Students identify the pattern in a problem. In this geometry lesson, students make predictions, collect and analyze data. They apply the idea of scales and measurements to the real world.