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Lesson Plan
EngageNY

Between-Figure and Within-Figure Ratios

For Teachers 9th - 10th Standards
Tie the unit together and see concepts click in your young mathematicians' minds. Scholars apply the properties of similar triangles to find heights of objects. They concentrate on the proportions built with known measures and solve to...
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Worksheet
Curated OER

Countdown Challenge: Similarity

For Students 7th - 8th
In this similarity worksheet, students observe similar rectangles and determine the length of the diagonal. They use words, symbols and diagrams to solve the problem and explain the results. This one-page worksheet contains one...
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Worksheet
Curated OER

Similarity: Instructional

For Students 7th - 8th
For this similarity worksheet, students solve and complete 7 different problems that include determining various dimensions of mirrors shown. First, they find the length of the diagonal of the large mirror in the diagram. Then, students...
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Interactive
Scholastic

Study Jams! Similar Figures

For Students 5th - 8th Standards
Discover how triangles are congruent based on their sides, angles, and proportionality. Learners explore the ways to determine similarity at their own pace, and then they practice afterwards with an assessment. 
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Worksheet
Curated OER

Identifying Similar Triangles

For Students 10th
In this identifying similar triangles worksheet, 10th graders solve 5 different proofs related to similar triangles. First, they identify the similar triangles in each figure and explain why they are similar, using the information to...
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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
EngageNY

Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles

For Students 9th - 10th Standards
Why are right triangles so special? Pupils begin their study of right triangles by examining similar right triangles. Verifying through proofs, scholars recognize the three similar right triangles formed by drawing the altitude. Once...
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Worksheet
Curated OER

Identify Similar Triangles With Proofs

For Students 10th - 12th
In this similar triangle worksheet, students write a two-column proof to explain why determined triangles are similar. Given some line lengths and angle measurements, students use proofs to identify the ratio of specified angles. This...
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Lesson Plan
EngageNY

Prove the Pythagorean Theorem Using Similarity

For Students 9th - 10th Standards
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.
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Lesson Plan
Willow Tree

Ratios and Proportions with Congruent and Similar Polygons

For Students 8th - 11th Standards
Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...
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Interactive
CK-12 Foundation

Pythagorean Theorem for Solving Right Triangles: Solving the Triangle

For Students 9th - 12th Standards
Observe the change in the trigonometric ratios as angles vary. An interactive provides the values of trigonometric ratios for both acute angles in a right triangle. Pupils create a right triangle to match given criteria and find the...
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Unit Plan
Curated OER

Zome System

For Teachers 4th - 6th
Get hundreds of interactive activity plans using the Zome Modeling System. Among dozens of lessons, a first exposure to similar triangles can be very visual for the learner. Here, young geometers explore the number of different shapes...
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Worksheet
Curated OER

Similar Triangles

For Students 10th
For this similar triangles worksheet, 10th graders solve and complete 10 different problems related to determining the sides of similar triangles. First, they write three equal ratios to show the corresponding sides that are...
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Lesson Plan
Curated OER

Ratios for Area and Volume

For Teachers 5th - 8th
In this ratios for area and volume worksheet, students solve problems where they find the ratios for problems of shapes dealing with area and volume. Students complete 4 problems.
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Lesson Plan
Curated OER

Similar Triangles

For Teachers 9th - 10th
Young scholars differentiate between similar and congruent triangles. In this geometry lesson, students identify the missing side and angle of a triangle. They identify the different ratio and proportion of the sides of a triangle.
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Lesson Plan
Curated OER

Similar Triangles

For Teachers 9th
Ninth graders find the height of every day objects using techniques learned through postulates that allow triangles in a problem to be similar. They calculate the length of a missing side and solve proportions.
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Lesson Plan
Curated OER

Similar Triangles - Applied Problems

For Teachers 9th - 12th
Students differentiate between similar and congruent triangles. In this geometry lesson, students identify the angles of triangles using the similarity theorem. They apply concepts of triangles to the real world.
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Activity
Curated OER

Triangle Series

For Teachers 9th - 12th Standards
Your algebra learners emphasize the"geometric" in geometric series as they use a common ratio between algebraic terms and find that it corresponds to a repeated similarity transformation. 
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Worksheet
Curated OER

Dilations and Similarity

For Students 8th - 10th Standards
In this dilations and similarity instructional activity, pupils solve 10 different problems that include various dilations. First, they determine the scale factor of dilations found in the illustrated graphs. Then, everyone determines...
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Lesson Plan
Curated OER

Similarity and Dilations - Discover Properties of Similar Figures

For Teachers 9th - 12th Standards
Learners investigate properties of similar figures. In this properties of similar figures lesson, pupils construct similar figures using Cabri Jr. They dilate their figure to create a similar one, and discuss the relationships between...
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Interactive
Curated OER

Similar Triangles Multiple Choice

For Students 8th - 10th
For this triangle relationships worksheet, students identify measurements in similar and congruent triangles. Each problem features a drawing of two or more triangles. Kids identify missing measurements. There are 5 multiple choice...
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Lesson Plan
Virginia Department of Education

Special Right Triangles and Right Triangle Trigonometry

For Teachers 9th - 11th Standards
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
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Lesson Plan
EngageNY

The Side-Angle-Side (SAS) and Side-Side-Side (SSS) Criteria for Two Triangles to Be Similar

For Students 9th - 10th Standards
Playing with mathematics can invoke curiosity and excitement. As pupils construct triangles with given criteria, they determine the necessary requirements to support similarity. After determining the criteria, they practice verifying...
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Activity
Exploratorium

Handy Measuring Ratio

For Teachers 4th - 8th Standards
Your hand can be a handy tool for measurement. Young mathematicians learn how to estimate the height of objects by applying similarity. They find the horizontal distance from the object where spreading their outstretched fingers results...