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Performance
Radford University

How Tall is the Tree?

For Teachers 9th - 12th Standards
Pairs or small groups work together to determine the height of a tree using similar triangles. Learners make a judgement which direction to let a tree fall to avoid hitting any structures. They then write letters to the principal...
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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
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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
Texas Instruments

What's the Trig?

For Teachers 9th - 12th Standards
Learners determine the trigonometric relationships within a triangle as they construct a right triangle on the Ti-89. They find the sine, cosine, and tangent of various angles of their triangle construction.
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Lesson Plan
Curated OER

Investigating Segments in a Triangle

For Teachers 9th - 12th Standards
Pupils investigate segments in a triangle by constructing a triangle using Cabri Jr. They construct segments within the triangle that lie on the midpoints of the triangle's sides. Learners then compare the slope of base of the triangle...
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Lesson Plan
Curated OER

Investigating Lengths of Segments in a Triangle

For Teachers 9th - 12th Standards
Pupils explore the midsegment of a triangle in the geometry lesson. They draw and measure the segment joining the midpoints of the two sides of a triangle and compare its length to the length of the third side of the triangle. The...
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Unknown Type
That Quiz

That Quiz: Practice Test: Triangles

For Students 9th - 10th Standards
Test your knowledge on the attributes of triangles. There are eleven levels that may be completed with or without a timer.
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Unit Plan
Sophia Learning

Sophia: Using Corresponding Parts of Congruent Triangles

For Students 9th - 10th Standards
This lesson will demonstrate the use of CPCTC in triangle congruency proofs.
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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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Unknown Type
Khan Academy

Khan Academy: Use Similar & Congruent Triangles

For Students 9th - 10th Standards
Solve geometry problems with various polygons by using all you know about similarity and congruence.
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Handout
Math Open Reference

Math Open Reference: Congruent Triangles

For Students 9th - 10th Standards
A complete reference guide to congruent triangles. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
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eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 1.4 Triangles

For Students 9th - 10th Standards
Explore and measure a variety of triangles.