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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.
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Worksheet
Curated OER

Similarity

For Students 10th
In this similarity worksheet, 10th graders solve and complete 14 different types of problems. First, they refer to each drawn figure given that the lines are parallel. Then, students find the length of each segment listed. In addition,...
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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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Lesson Plan
EngageNY

Incredibly Useful Ratios

For Students 9th - 10th Standards
Start the exploration of trigonometry off right! Pupils build on their understanding of similarity in this lesson that introduces the three trigonometric ratios. They first learn to identify opposite and adjacent sides before exploring...
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Unit Plan
Mathematics Vision Project

Module 4: Similarity and Right Triangle Trigonometry

For Teachers 9th - 12th Standards
Right you are to use a great resource. Starting with a lesson on dilations, scholars learn about similarity transformations and similar triangles. They use the knowledge to develop an understanding of right triangle trigonometry in later...
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Lesson Plan
Mathematics Assessment Project

Identifying Similar Triangles

For Teachers 7th - 9th Standards
Math whizzes work with angle sums and exterior angles to figure out the measure of other angles. This particular publication provides comprehensive support in the form of an anticipatory activity, questions designed to prompt discussion,...
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Lesson Plan
Curated OER

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

For Teachers 9th - 12th
Young scholars 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...
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Activity
Education Development Center

Similar Triangles

For Students 8th - 10th Standards
Model geometric concepts through a hands-on approach. Learners apply similar triangle relationships to solve for an unknown side length. Before they find the solution, they describe the transformation to help identify corresponding sides.
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Interactive
CK-12 Foundation

Pythagorean Theorem and Its Converse

For Students 8th - 10th
To be a right triangle, or not to be — that is the question. Scholars drag line segments in an Internet application to see if they form right triangles. Once they get the results of the activity, they connect them to the converse of the...
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Lesson Plan
Curated OER

Mathematical Modeling

For Teachers 9th - 12th
Study various types of mathematical models in this math lesson plan. Learners calculate the slope to determine the risk in a situation described. They respond to a number of questions and analyze their statistical data. Then, they...
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Interactive
CK-12 Foundation

Area Between Curves: Income and Expenses

For Students 11th - Higher Ed
Use the area of polygons to calculate the area between curves. Pupils calculate areas under income and expense curves by filling the space with squares and right triangles. Using that information, they determine the profit related to the...
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Interactive
CK-12 Foundation

Basic Trigonometric Functions: Ladder Length

For Students 9th - 12th Standards
Climb the ladder to trigonometry. The interactive introduces trigonometric ratios and finding lengths of sides of right triangles created by a ladder and a building. Learners use the interactive to create triangles by moving the top of...
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Interactive
CK-12 Foundation

Sine, Cosine, and Tangent Functions: Lighthouse

For Students 9th - 12th Standards
How far is that boat from the lighthouse? Scholars create diagrams to represent a scenario given the angle of depreciation from a lighthouse to a boat. Learners apply the basic trigonometric functions to find various distances stemming...
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Worksheet
Curated OER

Parts of Similar Triangles

For Students 10th
In this parts of similar triangles worksheet, 10th graders solve 6 different problems related to determining the value of various parts of similar triangles. First, they find the value of x in the 2 figures shown. Then, students find the...
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Lesson Plan
Mathematics Assessment Project

Deducting Relationships: Floodlight Shadows

For Teachers 9th - 12th Standards
Try to figure out what happens with shadows as a person moves between two light sources. A formative assessment lesson plan has individuals work on an assessment task based on similar triangles, then groups them based on their assessment...
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Lesson Plan
Curated OER

When Does SSA Work to Determine Triangle Congruence?

For Teachers 9th - 10th Standards
Your learners will make good use of the Socratic method in a collaborative task that begins with an assumed solution and ends with deeper understanding of the idea of determining two triangles congruent.
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Worksheet
Curated OER

Mean Twisters - Mean Proportional

For Students 9th - 10th
For this mean proportional worksheet, students work in pairs to solve right triangle problems. They use ratios and proportions of similar triangles to determine a missing length. This two-page worksheet contains 16 problems.
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Worksheet
Curated OER

Triangle Similarity

For Students 10th
In this triangle similarity learning exercise, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles...
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Lesson Plan
Curated OER

Similar Triangles and Proportions

For Teachers 9th - 12th Standards
Pupils investigate similar triangles and proportions as they make conjectures about the length of sides of similar triangles. For this lesson, have your class construct similar triangles using Cabri Jr so that they share a common vertex.
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Lesson Plan
Curated OER

Nested Similar Triangles

For Teachers 9th - 12th Standards
Nested triangles have been created so that they share a common vertex and vertex angle. Learners drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When...
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Worksheet
Curated OER

Similar Figures

For Students 10th
In this geometry worksheet students explore similar polygons and determine measure of missing sides and angles. Students use indirect measurement with similar triangles and determine the area and volume of similar figures. The seven page...
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Lesson Plan
Curated OER

Triangle Midsegment

For Teachers 9th - 12th Standards
Learn how to calculate the length and midsegments of triangles. Students differentiate between similar and congruent triangles. They create a spreadsheet with their findings.
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Lesson Plan
Curated OER

Similar Figures

For Teachers 9th - 12th Standards
Your class will use a TI calculator to drag vertices of rectangles and triangles to observe what happens to ratios of pairs of sides within each figure. They will apply the definition of similarity to identify similar shapes. The lesson...
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Lesson Plan
Curated OER

Corresponding Parts of Congruent Triangles

For Teachers 9th - 10th
Students identify different parts of a triangle. In this geometry lesson, students differentiate between similar and congruent triangles. They use the navigator to crate a visual of the different parts of a triangle.