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Handout
Oswego City School District

Regents Exam Prep Center: Theorems and Postulates for Geometry

For Students 9th - 10th Standards
Here is a partial list of theorems, postulates, and properties.
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Activity
Oswego City School District

Regents Exam Prep Center: Organizing and Venn Diagrams With Congruent Triangles

For Teachers 9th - 10th
As a resource for teachers, an activity of how to connect Venn Diagrams with the five methods of proving triangles congruent - SSS, SAS, ASA, AAS, HL - is explained.
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eBook
Mathigon

Mathigon: Geometry: Triangles and Trigonometry: Triangles Congruence

For Students 9th - 10th Standards
This lesson focuses on triangle congruence; it shows the ways to prove that triangles are congruent.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Why Does Asa Work?

For Teachers 9th - 10th Standards
In triangles ABC and ABD, we are given that angle BAC is congruent to angle BAD and angle ABC is congruent to angle ABD. Show that the reflection of the plane about line AB maps triangle ABD to triangle ABC. Aligns with G-CO.B.8.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co When Does Ssa Determine Triangle Congruence?

For Teachers 9th - 10th Standards
In this task, we are told that two triangles share two sets of congruent sides and one pair of congruent angles and that these two triangles must be congruent based on the reasoning given. Students are asked to analyze this reasoning to...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co, G Srt Congruence of Parallelograms

For Teachers 9th - 10th Standards
In this task, a student has learned the SSS and SAS congruence tests for triangles and wonders if these tests might work for parallelograms. Aligns with G-CO.C.11 and G-SRT.B.5
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Properties of Congruent Triangles

For Teachers 9th - 10th Standards
The goal of this task is to understand how congruence of triangles, defined in terms of rigid motions, relates to the corresponding sides and angles of triangles. Aligns with G-CO.B.7.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Are the Triangles Congruent?

For Teachers 9th - 10th Standards
In each of the following diagrams, two triangles are shaded. Based on the information given about each diagram, decide whether there is enough information to prove that the two triangles are congruent. Aligns with G-CO.B.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Showing a Triangle Congruence: The General Case

For Teachers 9th - 10th Standards
Given distinct, congruent triangles, students are asked to show that congruence can always be shown with one, two, or three rigid motions. Aligns with G-CO.A.5.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Showing a Triangle Congruence: A Particular Case

For Teachers 9th - 10th Standards
Given two congruent triangles, students are asked to analyze the effects of different transformations. Aligns with G-CO.A.5.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g, G Gpe, G Srt, G Co Is This a Rectangle?

For Teachers 9th - 10th Standards
For this task, students are given four sets of coordinate pairs and are asked to determine if they represent a rectangle. Aligns with 8.G.A, 8.G.B, G-CO.B, G-GPE.B, and G-SRT.B.5.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Triangle Congruence With Coordinates

For Teachers 8th Standards
For this task, 8th graders explore congruence and transformations of two triangles on a coordinate grid. Aligns with 8.G.A.2.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Congruent Triangles

For Teachers 8th Standards
In this task, 8th graders investigate congruence and transformations of two triangles on a coordinate grid. Includes a GeoGebra worksheet that the teacher can use for demonstration purposes. Aligns with 8.G.A.2.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Cutting a Rectangle Into Two Congruent Triangles

For Teachers 8th Standards
This task shows the congruence of two triangles formed by cutting a rectangle in half along the diagonal. Students are asked to investigate elements of congruence and transformations among the shapes. Aligns with 8.G.A.2.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Why Does Sss Work?

For Teachers 9th - 10th Standards
In this task, students must show that two triangles are congruent given a set of steps which produce a rigid transformation of the plane. Includes an experimental GeoGebra worksheet that instructors can use to demonstrate the task....
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Why Does Sas Work?

For Teachers 9th - 10th Standards
In this task, young scholars must explain the given reasoning for why triangle ABC is congruent to triangle DEF using the language of reflections. Aligns with G-CO.B.8.
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Interactive
Math Open Reference

Math Open Reference: Congruence

For Students 9th - 10th Standards
A complete reference guide to congruence including congruent triangles and polygons. It provides definitions, animation, and interactive activities that enhance further explanation.
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Unit Plan
Math Open Reference

Math Open Reference: Triangles

For Students 9th - 10th Standards
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
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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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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Congruent Triangles

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] In this lesson students determine whether two triangles are congruent. Students examine guided notes, review guided practice, watch instructional videos and attempt...
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Congruent Triangles

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept teaches students what it means for two triangles to be congruent and how to identify corresponding parts of congruent triangles. Students examine guided...
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Unit Plan
CK-12 Foundation

Ck 12: Geometry: Sss 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-Side-Side shortcut.
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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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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.