Curated OER
Transformations and Congruence
In this transformations and congruence worksheet, 10th graders solve and complete 5 different types of problems. First, they calculate the length of a line giving their answer in 3 significant figures. Then, students prove that two...
EngageNY
Law of Sines
Prove the Law of Sines two ways. The ninth segment in a series of 16 introduces the Law of Sines to help the class find lengths of sides in oblique triangles. Pupils develop a proof of the Law of Sines by drawing an altitude and a second...
Curated OER
Proofs
In this proofs learning exercise, 10th graders solve and graph 8 different equations. First, they prove that each triangle is either congruent or similar. Then, students use the concept of corresponding parts of congruent triangles to...
Curated OER
Congruent Triangles Homework
In this geometry activity, students use proofs to solve properties of triangles. They differentiate between congruent and similar triangles. There are 15 questions.
Curated OER
Indirect Euclidean Proofs
In this indirect Euclidean proof worksheet, students write statements supporting the reasons for a given proof. This one-page worksheet contains ten problems.
Curated OER
Proofs Involving Congruent Angles
In this congruent triangle worksheet, students write proofs to support characteristics of congruent triangles. This one-page worksheet contains ten problems.
Curated OER
Proving Triangles Congruent
In this proving triangles congruent worksheet, 10th graders solve 5 different problems that include proofs and proving congruence in triangles. First, they determine which postulate can be used to prove the triangles congruent and mark...
Curated OER
Identifying Similar Triangles
For this identifying similar triangles worksheet, 10th graders solve 5 different proofs related to similar triangles. First, they identify the similar triangles in each figure and explain why they are similar, using the information to...
Curated OER
Proofs with Triangles
In this geometry worksheet, students prove triangle congruence by making statements with reasons and concluding with the AAS or HL theorem. There are 2 proofs.
Curated OER
Reflections and Equilateral Triangles
Your learners collaboratively find the lines of symmetry in an equilateral triangle using rigid transformations and symmetry. Through congruence proofs they show that they understand congruence in terms of rigid motions as they prove...
EngageNY
End-of-Module Assessment Task - Geometry (module 1)
Have you hit a wall when trying to create performance task questions? Several open-ended response questions require a deep level of thinking. Topics include triangle congruence, quadrilaterals, special segments, constructions, and...
EngageNY
Review of the Assumptions (part 2)
Is the amount of information getting overwhelming for your geometry classes? Use this strategy as a way to organize information. The resource provides a handout of information studied in relation to triangle congruence. It includes a...
Curated OER
Self-Check for Triangle Congruence Proofs Multiple Choice
In this triangle congruence learning exercise, learners select the postulate that is being illustrated to prove congruence between triangles. The learning exercise is self-scoring. Once students select the "check your work" link, they...
Curated OER
Indirect Proof and Inequalities in One Triangle
In this geometry worksheet, 10th graders order the sides and angles of a triangle and determine the range of the third side of a triangle given the lengths of two sides. The one page worksheet contains sixteen questions. Answers are...
Mathematics Vision Project
Module 6: Congruence, Construction, and Proof
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This unit...
Curated OER
Isosceles Triangles
Students identify the properties of an isosceles triangle. In this geometry lesson, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
Curated OER
Indirect Euclidean Proofs
In this Euclidean proofs worksheet, 10th graders solve 10 different problems that include completing indirect Euclidean proofs. First, they write a statement for each of the reasons listed on the sheet of proofs. Then, students solve the...
Curated OER
Right Triangles
In this right triangles worksheet, 10th graders solve 6 various problems and figures related to right triangles. First they identify and describe the 3 theorems and 1 postulate stated that prove 2 right triangles congruent if one of them...
Curated OER
Proving Triangles Congruent
Students examine Triangle Congruency. In this measurement comparison lesson, students use inductive, deductive and analytical thinking skills to prove triangle congruency. Students analyze and record their findings on activity worksheets.
Curated OER
Proving Figures Congruent
In this proving figures congruent worksheet, 10th graders solve and complete 11 different problems. First, they determine the additional information needed to prove the triangles congruent. Then, students determine which postulate, if...
Illustrative Mathematics
Applying the Pythagorean Theorem in a Mathematical Context
Participants who use this resource will apply the Pythagorean Theorem to show whether or not the shaded triangle inscribed in a rectangle is a right triangle. Once all of the sides on the shaded triangle are found, it is important that...
Curated OER
As the Bird Flies
Students investigate the properties of lines and congruent triangle theorems as well as apply geometric properties and relationships to real-world mathematical problems. Given two different scenarios, they examine maps that have been...
Curated OER
Right Triangles
In this right triangles learning exercise, 10th graders solve 5 problems that relate to different right triangles. First, they find the values of x and y so that each triangle is congruent to the other. Then, students write a two-column...
Illustrative Mathematics
Reflections and Isosceles Triangles
Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The...