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Lesson Plan
Curated OER

Finding the Area of an Equilateral Triangle

For Teachers 9th - 11th Standards
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
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Lesson Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
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Interactive
CK-12 Foundation

Pythagorean Theorem to Classify Triangles: Missing Angles

For Students 8th - 12th Standards
Learn to use the Pythagorean Theorem with non-right triangles. Pupils use the interactive to discover the relationship between the lengths of sides for acute and obtuse triangles. They compare the squares of the sides of the triangles to...
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Lesson Plan
Captain Planet Foundation

Frog Garden Party! Toads and Triangles in the Math Garden

For Teachers 4th Standards
It's frog party time! With frog banners, frog juice, and a triangle hunt, your garden party is sure to be both entertaining and educational. The lesson connects geometry, earth science, and delicious snacks to teach kids about ecosystems...
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Lesson Plan
Mathalicious

Been Caught Stealing

For Teachers 6th - 8th Standards
You're safe, when calculating the odds of stealing second base! Learners compare the rate of a runner to the distance the ball travels, in a lesson plan that explores right triangles and measurement. Full of discussion questions and fun...
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Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 10th - 12th
In this triangle worksheet, students explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
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Lesson Plan
Curated OER

Principles of Square Roots Lesson Plan

For Teachers 8th - 11th
Middle and high schoolers investigate all the different places in math that square root is present. In this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...
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Interactive
CK-12 Foundation

Identifying Sets of Pythagorean Triples: Matching Problem

For Students 8th - 12th Standards
What sets of whole numbers make up the measures of side lengths in right triangles? Pupils use an interactive triangle to learn about Pythagorean triples. Individuals find missing values in triples and learn more about Pythagorean...
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Lesson Plan
Curated OER

Learning Unit: The Pythagorean Theorem

For Teachers 8th - 10th
Middle and high schoolers research the life of Pythagoras and the Pythagorean theorem. They write a short biography of Pythagoras and learn to apply the theorem in their study of right triangles.
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Worksheet
Curated OER

Finding Angles in Right Triangles

For Students 10th
In this geometry worksheet, 10th graders use right triangle trigonometry to solve application problems in which they find the measure of the missing angle in a right triangle.  The two page worksheet contains five free response...
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Lesson Plan
Curated OER

Applying Special Right Triangles

For Teachers 10th
In this geometry worksheet, 10th graders use the theorems regarding right triangles to find the missing length in a special right triangle. The one page worksheet contains eleven questions. Answers are included.
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Interactive1:45
Scholastic

Study Jams! Classify Triangles

For Students 5th - 8th Standards
Jam on with this multi-faceted activity teaching triangle classification. Start with a learner-paced lesson describing the different qualities of triangles and follow with a fun karaoke session. Also provided are two types of...
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Lesson Plan
Curated OER

Right Triangles

For Teachers 4th - 8th
Learners classify triangles and make connections regarding angle measurements and attributes of acute, right, and obtuse triangles. They listen to teacher define and explain triangles. Everyone imagines a place where a broken wing for a...
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Assessment
Inside Mathematics

Hopewell Geometry

For Teachers 9th - 12th Standards
The Hopewell people of the central Ohio Valley used right triangles in the construction of earthworks. Pupils use the Pythagorean Theorem to determine missing dimensions of right triangles used by the Hopewell people. The assessment task...
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Unit Plan
Mathematics Vision Project

Module 7: Modeling with Geometry

For Teachers 9th - 12th Standards
Model good modeling practices. Young mathematicians first learn about cross sections and solids of revolution. They then turn their attention to special right triangles and to the Laws of Sine and Cosine.
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Unit Plan
Mathematics Vision Project

Module 5: Modeling with Geometry

For Students 9th - 12th Standards
Solids come in many shapes and sizes. Using geometry, scholars create two-dimensional cross-sections of various three-dimensional objects. They develop the lesson further by finding the volume of solids. The module then shifts to finding...
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Assessment
Inside Mathematics

Circles in Triangles

For Teachers 9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
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Interactive
Curated OER

Mixed Right Triangles

For Students 10th
In this geometry worksheet, 10th graders use right triangle trigonometry to find the missing angle measure or side length in right triangles. The one page interactive worksheet contains ten questions. Answers and hints are included. 
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Activity
Teach Engineering

Stay in Shape

For Teachers 7th - 9th Standards
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
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Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve and complete 12 different types of problems. First, they solve for a variable given each of the right triangles with the sides as indicated. Then, students determine the shorter...
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Worksheet
Curated OER

Right Triangles

For Students 10th
For this right triangles worksheet, 10th graders solve 10 different problems that include determining the means proportionally in each right triangle. First, they use the given information to determine the measure of each line segment....
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Worksheet
Curated OER

Right Triangles & Pythagorean Theorem

For Students 6th - 8th
In this math activity, students find the missing angles for the right triangles using the Pythagorean Theorem. Then they label the adjacent and opposite angles.
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Lesson Plan
Curated OER

Acute Triangles

For Teachers 4th - 8th
Learners study acute triangles. They measure angles using a protractor, then classify the triangles as either right, obtuse, or acute. Everyone creates a design for a Navajo rug using only acute triangles.
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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 instructional activity that also provides a proof by contradiction of the converse. Pupils use the converse to determine whether...