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Lesson Plan
EngageNY

Applications of Congruence in Terms of Rigid Motions

For Students 9th - 10th Standards
Corresponding parts, congruent parts, congruent corresponding parts—what does it all mean? The resource challenges pupils to identify corresponding parts for pairs of figures. It uses examples of figures that undergo rigid...
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Activity
Illustrative Mathematics

Congruent Triangles

For Teachers 7th - 9th Standards
Geometers prove that triangle PQR is congruent to triangle ABC by describing any combination of rotations, reflections, and translations that would prove it so. There is only this single task on the handout, but a detailed explanation of...
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Handout
Mt. San Antonio Collage

Congruent Triangles Applications

For Students 9th - 12th Standards
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the worksheet provides a brief introduction of the different properties and postulates. The remaining pages contain...
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Unit Plan
1
1
Mathematics Vision Project

Similarity and Right Triangle Trigonometry

For Teachers 10th - 12th Standards
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
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Lesson Plan
Curated OER

Tile Patterns I: Octagons and Squares

For Teachers 7th - 9th Standards
This can be used as a critical thinking exercise in congruence or as a teaching tool when first introducing the concept. Four octagons are arranged in such a way that a square is formed in the middle. With this information, geometry...
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Lesson Plan
Curated OER

An Application of Congruence

For Teachers 9th - 10th
Learners solve triangles using the properties if congruency. In this geometry lesson, students apply congruent and similar figures to solve real world and math problems. They show they are able to follow instructions.
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Interactive
Curated OER

Trigonometry Applications

For Students 10th
In this geometry worksheet, 10th graders solve application word problems involving the use or right triangle trigonometry, including angle of elevation or depression. The one page interactive worksheet contains five questions. Hints,...
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Lesson Plan
EngageNY

Properties of Parallelograms

For Teachers 9th - 10th Standards
Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...
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Lesson Plan
1
1
Illustrative Mathematics

Eratosthenes and the Circumference of the Earth

For Teachers 9th - 12th Standards
The class gets to practice being a mathematician in ancient Greece, performing geometric application problems in the way of Eratosthenes. After following the steps of the great mathematicians, they then compare the (surprisingly...
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Lesson Plan
Curated OER

Congruent Triangles

For Teachers 9th - 12th
Students explore the concept of congruent triangles.  For this congruent triangles lesson, students use Cabri Jr. to construct two congruent triangles using circles.  Students determine if the two triangles are congruent by using the...
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Unit Plan
1
1
EngageNY

Congruence, Proof, and Constructions

For Teachers 8th - 10th Standards
This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons is broken...
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Worksheet
Curated OER

Complementary and Supplementary Angles

For Students 4th - 7th
Your geometry learners determine the measure of remaining angles in sets of three given that the other two are complementary or supplementary. From a diagram, they identify which angles are supplementary, complementary or congruent from...
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Lesson Plan
Curated OER

Triangles & Congruence, Proportions & Similarity, Right Triangle & Trigonometry

For Teachers 9th - 12th
Students are introduced to the topic of congruence and proportions in Geometry. Using technology, they construct and validate the properties of various geometric figures and identify whether it is congruent or proportion to the objects...
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Worksheet
Curated OER

Proportional Reasoning: Ratio Applications

For Students 8th
For this ratio applications worksheet, 8th graders solve and complete 24 various types of problems that include proportional reasoning. First, they solve each pair of similar figures for the given variable. Then, students write and solve...
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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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Instructional Video14:29
2
2
Flipped Math

Addition Postulate

For Students 9th - 12th Standards
Add a little algebra to the geometry. Class members learn about the Addition Postulate for segments and angles. The pupils use their knowledge of solving equations to find lengths of segments and measures of angles. Individuals apply...
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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

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

For Teachers 9th - 10th
Young scholars 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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Lesson Plan
Curated OER

Congruent Triangles

For Teachers 10th
Tenth graders explore congruent triangles.  In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles are congruent by SSS, ASA, AAS, or SAS. 
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Lesson Plan
Curated OER

Building Congruent Triangles

For Teachers K - 12th
Students differentiate between congruent and similar triangles. In this geometry instructional activity, students identify the lengths and angle measures of triangles. They use postulates to prove their answers.
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Lesson Plan
EngageNY

Review of the Assumptions (part 2)

For Students 9th - 10th Standards
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...
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Lesson Plan
EngageNY

Base Angles of Isosceles Triangles

For Students 9th - 10th Standards
Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...
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Instructional Video17:08
2
2
Flipped Math

Measuring Angles

For Students 9th - 12th Standards
An informative presentation shows pupils how to name and measure angles. Scholars revisit the different types of angles and their definitions and use their knowledge of what an angle bisector is to solve algebraic problems. At the end,...
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Worksheet
Curated OER

Challenge: Skills and Applications Lesson 1.3

For Students 10th - 12th
In this skills worksheet, learners explain the Segment Addition Postulate, provide examples and counter examples and determine congruent line segments.  This one-page worksheet contains 11 multi-step problems.