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Lesson Plan
EngageNY

The Converse of the Pythagorean Theorem

For Teachers 8th Standards
Is it a right triangle or not? Introduce scholars to the converse of the Pythagorean Theorem with a lesson that also provides a proof by contradiction of the converse. Pupils use the converse to determine whether triangles with given...
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Worksheet
Curated OER

Why do Stars Rise in the East?

For Students 8th - 10th
In this stars rise in the east worksheet, students use geometry to show how the Earth rotates from west to east and why celestial bodies appear to rise in the east and set in the west. Students draw a figure and label given points in...
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Worksheet
Curated OER

Identify Similar Triangles With Proofs

For Students 10th - 12th
In this similar triangle worksheet, students write a two-column proof to explain why determined triangles are similar. Given some line lengths and angle measurements, students use proofs to identify the ratio of specified angles. This...
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Worksheet
Curated OER

Pre-Proof Warm-Ups

For Students 10th
In this pre-proofs worksheet, 10th graders solve and complete 10 different problems that include various proofs and their definitions. They use the diagram shown and the given information to write the direct conclusion for each case....
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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that include various forms of triangles. First, they name the method for proving each set of triangles congruent using the given information....
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Worksheet
Curated OER

Geometry Proofs

For Students 10th
In this geometry proofs worksheet, 10th graders solve and complete 6 different problems that include various proofs. First, they prove a triangle has equivalent angles as given. Then, students prove two angles supplementary as described.
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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems to determine whether each set of triangles is congruent or not. First, they copy each diagram onto a piece of paper and mark up the paper with...
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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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Worksheet
Curated OER

Congruent Triangles

For Students 10th
In this geometry worksheet, 10th graders identify the corresponding parts of congruent triangles.  The one page worksheet contains four problems.  Answers are not provided. 
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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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Worksheet
Curated OER

More Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve 5 various types of geometry problems related to triangles. First, they draw and label triangles, indicating the additional pairs of corresponding parts that would have to be...
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Worksheet
Curated OER

Proofs with Triangles

For Students 9th - 12th
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.
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Worksheet
Curated OER

Circle Proofs

For Students 10th
In this circle proofs worksheet, 10th graders complete 4 different problems that include circle proofs. They respond to each of the questions that deal with circle proofs. Then, students read the given information and use the circle...
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Activity
Illustrative Mathematics

Reflections and Isosceles Triangles

For Teachers 9th - 11th Standards
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...
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Worksheet
Curated OER

Indirect Euclidean Proofs

For Students 10th
In this Euclidean proofs activity, 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...
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Worksheet
Curated OER

Indirect Euclidean Proofs

For Students 7th - 8th
For this indirect Euclidean proof worksheet, students write statements supporting the reasons for a given proof. This one-page worksheet contains ten problems.
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Worksheet
Curated OER

Inscribed Angles

For Students 10th
In this inscribed angles worksheet, 10th graders solve 13 various types of problems related to inscribed angles in geometry. First, they identify a circle illustrated and each arc of the circle. They, students find the measure of each...
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Worksheet
Curated OER

Proofs with Triangles

For Students 9th - 10th
In this geometry worksheet, student solve problems with triangles using proofs. They identify the solution based on SSS, SAS, ASA. There are 5 proofs tobe completed.
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Worksheet
Curated OER

Congruent Triangles Homework

For Students 9th - 10th
In this geometry instructional activity, students use proofs to solve properties of triangles. They differentiate between congruent and similar triangles. There are 15 questions.
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Worksheet
Curated OER

SSS, SAS, ASA, and AAS Congruence

For Students 8th - 10th
Students will determine if triangles are congruent and state the appropriate congruence theorem. In this geometry lesson, students will determine what information is needed to determine if a pair of triangles are congruent using ASA,...
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Worksheet
Curated OER

The Premises of Geometry

For Students 9th - 10th
In this geometry activity, students solve for missing midpoints, segments and angles using algebraic equations. They use geometric properties to solve these equations. There are 32 questions on 7 different worksheets.
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Assessment
Inside Mathematics

Rhombuses

For Teachers 9th - 12th Standards
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...
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Worksheet
Curated OER

Angles in Polygons

For Students 10th
For this geometry worksheet, 10th graders solve problems involving quadrilaterals using the angle sum of quadrilaterals. They solve for linear pairs, opposite angle theorem and triangular angles. There are 5 questions.
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Worksheet
Curated OER

Triangles

For Students 10th
In this geometry worksheet, 10th graders solve problems involving triangular inequality. They apply the proofs and theorem of triangles to solve these problems. There is an overview and one question.