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Lesson Plan
Curated OER

Similar Triangles

For Teachers 9th
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.
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Lesson Plan
Curated OER

CSI Investigation of Congruence and Similarity

For Teachers 9th - 12th
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.
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Lesson Plan
Curated OER

Navy Sail Design

For Teachers 9th - 12th
Learners use the Pythagorean Theorem to explore sailboat design. In this Pythagorean Theorem lesson, two sides of a triangular sail are measured, and the theorem is used to calculate the third side. A worksheet, bulletin board design,...
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Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
Students engage in a lesson plan 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...
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Handout
Lockport City School District

Reasons for Geometric Statement/Reason Proofs

For Students 8th - 11th Standards
Stuck trying to remember the formal language of a geometric proof? Never fear, this handout has them all ready to go. The reasons are sectioned by topic so this handy guide is ready when you are to tackle those two column proofs. 
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Worksheet
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Jesuit High School

Geometry Sample Problems

For Students 8th - 11th Standards
I'd like to prove that this worksheet has a lot to offer. Seven problems using triangles and parallelograms practice the traditional method of a two-column proof. After the worksheet is some practice problems that show worked out...
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Lesson Plan
Curated OER

Why can't We Use SSA to Prove Triangles Congruent?

For Teachers 9th - 10th
Learners investigate triangles and congruences. In this geometry lesson, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
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Handout
CK-12 Foundation

Ck 12: Geometry: Angles and Transversals Study Guide

For Students 9th - 10th Standards
This study guide on angles and transversals covers key terms, angle types formed by transversals, postulates and theorems about transversals, and how to prove if lines are parallel or perpendicular. It is available for download with free...
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Asa and Aas Triangle Congruence

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two triangles are congruent with the Angle-Side-Angle and Angle-Angle-Side shortcuts. Students examine guided notes, review guided...
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Sas Triangle Congruence

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] Prove two triangles are congruent with the Side-Angle-Side shortcut.
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Lesson Plan
Other

Nearpod: Congruent Triangles & Similarity

For Teachers 9th - 10th Standards
In this lesson on congruent triangles, students explore how to use postulates to identify if triangles are congruent by SSS, SAS, ASA, and AAS.
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Activity
Analyze Math

Analyze Math: Congruent Triangle Examples

For Students 9th - 10th Standards
The geometry tutorial investigates congruent triangles. Students learn about the definitions and theorems on congruent triangles. Some topics included are angle-side-angle, side-side-side, and side-angle-side congruence postulates. The...
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Handout
CK-12 Foundation

Ck 12: Geometry: Triangle Congruence Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] Provides an overview of triangle congruence, including key terms, properties of congruent triangles, triangle postulates and theorems, and special triangles.
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Whiteboard
ClassFlow

Class Flow: Congruence in Triangles

For Teachers 9th - 10th Standards
[Free Registration/Login Required] This lesson helps teach congrence in triangles. Includes practice with postulates, theorems, and logical reasoning.
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Sas Triangle Congruence

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept introduces students to the SAS Triangle Postulate and how to prove that two triangles are congruent given only information about two pairs of sides and...