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Lesson Plan
Curated OER

Right Triangle Geometry

For Teachers 9th - 11th
Students study the basic principles of right triangle geometry needed to solve for unknown values of a right triangle. They apply and master the principles of right triangle geometry by solving problems.
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Worksheet
Curated OER

Classifying Triangles Using Sides

For Students 4th - 5th
In this geometry worksheet, students answer 8 fill in the blank questions where they must examine 5 different complex geometric figures to classify triangles.
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Lesson Plan
Curated OER

Special Right Triangles

For Teachers 7th - 9th
Students identify the different parts of a right triangle. In this geometry lesson, students use the Pythagorean Theorem to identify missing sides and angles of a right triangle. They work with irrational and rational roots.
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Worksheet
Curated OER

Similar Right Triangles-Introductions to Trigonometry

For Students 9th - 10th
In this geometry worksheet, students examine similar right triangles as the basis for the foundation of trigonometry. Students define the basic trigonometric functions and use a calculator to find the trigonometric value of an angle. The...
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Lesson Plan
Curated OER

Right Triangles and The Unit Circle

For Teachers 8th - 10th
Learners solve right triangles using trigonometry. In this geometry lesson plan, students use the unit circle to identify different trig values. They identify the six trigonometric identities.
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Worksheet
Curated OER

Right Triangle

For Students 8th - 9th
In this right triangle worksheet, students find the length of sides of a right triangle. This one-page worksheet contains 1 problem.
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Worksheet
Curated OER

Right Triangle

For Students 8th - 9th
In this right triangle worksheet, learners find the lengths of the sides of a triangle. This one-page worksheet contains 1 problem.
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Lesson Plan
Curated OER

Right Triangles and The Pythagorean Theorem

For Teachers 8th - 9th
Learners play a game to reinforce concepts of the Pythagorean Theorem. In this geometry lesson, students find the missing angle and lengths of a right triangle. They use properties of trigonometry about sine, cosine and tangent to solve...
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Lesson Plan
EngageNY

The Definition of Sine, Cosine, and Tangent

For Students 9th - 10th Standards
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar triangles. 
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Worksheet
K12 Reader

Classifying Triangles

For Students 2nd - 3rd Standards
Bring math and reading informational text together with a reading comprehension lesson. After kids read about isosceles, scalene, and equilateral triangles, they answer five comprehension questions to demonstrate how they can use context...
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Lesson Plan
Mathematics Assessment Project

Solving Problems with Circles and Triangles

For Teachers 9th - 12th Standards
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 7th - 10th
In this measurement lesson plan, learners examine the Pythagorean Theorem, perimeter, and areas of right triangles. They record their measurements and research their findings on a grid.
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Lesson Plan
EngageNY

Unknown Angles

For Students 9th - 10th Standards
How do you solve an equation like trigonometry? Learners apply their understanding of trigonometric ratios to find unknown angles in right triangles. They learn the meaning of arcsine, arccosine, and arctangent. Problems include basic...
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Handout
McGraw Hill

Triangles

For Students 4th - 7th Standards
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of similar...
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Assessment
Concord Consortium

Isosceles Triangle Spaces

For Students 7th - 10th Standards
How many different types of triangles can your class name? A discovery lesson guides learners through an exploration of the different triangle types and the relationships between their angles and sides. Using coordinate geometry,...
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Lesson Plan
Everyday Mathematics

Mathematics Within: Slope and Triangles

For Teachers 8th - 10th Standards
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
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Lesson Plan
Curated OER

Discover the Pythagorean Theorem

For Teachers 6th - 8th
Middle schoolers explore the Pythagoras theorem. In this geometry lesson, students make right triangles and identify the parts of the triangle. Middle schoolers complete measurements of the sides of the triangle.
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Lesson Plan
Curated OER

Indirect Proof and Inequalities in one Triangle

For Teachers 10th
In this geometry worksheet, 10th graders complete an indirect proof and order the sides or angles of a triangle. Also, students determine if a triangle can have sides with the given lengths. The two page worksheet contains twelve...
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Assessment
EngageNY

End-of-Module Assessment Task - Geometry (module 2)

For Students 9th - 10th Standards
Increase the level of assessment rigor with the test of performance tasks. Topics include similar triangles, trigonometric ratios, Law of Sines, Law of Cosines, and trigonometric problem solving. 
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Lesson Plan
Curated OER

Geometric Properties

For Teachers 9th - 12th
Students find triangular angles using the angle theorem. In this geometry lesson, students describe labeled triangles, use the pythagorean theorem, and rewrite information about triangles in standard form.
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Lesson Plan
EngageNY

Solving Problems Using Sine and Cosine

For Students 9th - 10th Standards
Concepts are only valuable if they are applicable. An informative resource uses concepts developed in lessons 26 and 27 in a 36-part series. Scholars write equations and solve for missing side lengths for given right triangles. When...
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Lesson Plan
EngageNY

Perimeter and Area of Triangles in the Cartesian Plane

For Students 9th - 12th Standards
Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They then...
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Lesson Plan
Illustrative Mathematics

Two Wheels and a Belt

For Teachers 9th - 10th Standards
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
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Interactive
CK-12 Foundation

Angles of Elevation and Depression: Fly-By Calibration

For Students 9th - 12th Standards
Determine the distance between two trees from afar. Pupils use an interactive resource to create two right triangles using trees and a plane. They determine the horizontal legs of each triangle to find the distance between the two trees.