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Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles learning exercise, 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...
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Lesson Plan
Curated OER

Proofs of the Pythagorean Theorem

For Teachers 9th - 12th Standards
Working individually and collaboratively, geometers gain a clear understanding of the Pythagorean theorem. They create, explain, and compare proofs of the theorem. Proofs involve areas of trapezoids, squares, and triangles, congruent...
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Worksheet
Curated OER

Transformations and Congruence

For Students 10th
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...
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Lesson Plan
Curated OER

Similarity and Congruence

For Teachers 9th - 12th
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.
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Worksheet
Curated OER

Quiz: Beginning Congruent Triangle Proofs

For Students 10th - 11th
In this congruent triangle proof worksheet, students write theorems to prove the congruence of given triangles. This one-page worksheet contains three given polygons to prove congruence.
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Worksheet
Curated OER

Using Congruent Triangles

For Students 10th
In this geometry worksheet, 10th graders use basic knowledge of congruent triangles (CPCTC) to prove that the given triangles are congruent.  The one page worksheet contains four problems.  Answers are not included. 
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Worksheet
Curated OER

Triangle worksheets

For Students 10th
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
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Assessment
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1
Curated OER

Congruent Segments

For Students 7th - 9th Standards
The task, should your class decide to take it, is to list a series of reflections that transfer a line segment from one position to another. 
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Lesson Plan
Curated OER

Congruent Triangles

For Teachers 9th - 12th Standards
Students identify properties of triangles. For this geometry lesson, students differentiate between similar and congruent triangles. They use the umber of sides to help define the angle of the polygon.
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Lesson Plan
Curated OER

Reflections and Equilateral Triangles

For Teachers 9th - 10th Standards
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...
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Worksheet
Curated OER

Quiz: Geometric Constructions-Congruence

For Students Higher Ed
In this congruent figures worksheet, students answer ten true or false questions. A sample question reads: "Two triangles are congruent when their shape and size will be the same."
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Worksheet
Curated OER

More Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve 6 various forms of problems that include a proof and a word problem. First, they draw and label triangles and indicate the additional pairs of corresponding parts that would have...
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Lesson Plan
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Illustrative Mathematics

Why Does SSS Work?

For Teachers 9th - 10th Standards
While it may seem incredibly obvious to the geometry student that congruent sides make congruent triangles, the proving of this by definition actually takes a bit of work. This exercise steps the class through this kind of proof by...
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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 13 different problems. First, they use the illustrated congruent triangles to show other congruency in each problem. Then, students determine and prove the angle...
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Lesson Plan
Curated OER

Similarity and Congruence

For Teachers 9th - 12th
Students explore the concept of similarity and congruence. In this similarity and congruence lesson plan, students cut out strips of paper and form a triangle. Students try to prove that their triangles are congruent using the SSS...
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Worksheet
Curated OER

Proofs Involving Congruent Angles

For Students 11th - 12th
In this congruent triangle worksheet, students write proofs to support characteristics of congruent triangles. This one-page worksheet contains ten problems.
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Lesson Plan
Curated OER

Constructions of Isosceles and Equilateral Triangles

For Teachers 4th - 9th
Students explore the difference between drawing and constructing a triangle utilizing The Geometer's Sketchpad on the computer. They create, develop and script constructions for both isosceles and equilateral triangles. Each student has...
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Assessment
Math Worksheets Center

Congruent Triangle Proofs Quiz

For Students 9th - 12th
A congruent triangles quiz challenges teenage mathematicians to complete a pair of geometric proofs. Each problem includes a picture of the triangles in question, a given set of information, and the five steps needed to finish the proof....
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Worksheet
Curated OER

Identifying Similar Triangles

For Students 10th
In 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...
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Lesson Plan
Curated OER

Triangles in Architecture

For Teachers 10th - 12th
Learners find triangles in the real world. For this geometry lesson, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
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Lesson Plan
Futures Channel

Folding Circles

For Teachers 7th - 12th Standards
Students investigate properties of circles. In this geometry lesson, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
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Unit Plan
Mathematics Vision Project

Module 6: Congruence, Construction, and Proof

For Teachers 8th - 10th Standards
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...
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Activity
Curated OER

Inscribing a Square in a Circle

For Teachers 9th - 11th Standards
Inscribing a square in a circle brings up a number of interesting geometry topics including triangle congruence and how to prove a quadrilateral is a square. This activity is followed up by finding the area of the square and determining...
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Lesson Plan
Curated OER

Triangle Proofs

For Teachers 10th
Tenth graders complete a unit of lessons on congruent triangles and triangle proofs. They observe and participate in teacher-led discussions of examples of the methods to prove that triangles are congruent, and create an original proof.