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Lesson Plan
Curated OER

Angles and Similarity

For Teachers 9th - 12th Standards
Students identify triangles as similar or congruent. In this geometry lesson, students drag triangles around on the navigator to see the effect of different angles on the shape of the triangle. They discuss angle similarity and angle...
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Lesson Plan
Curated OER

Trigonometry Ratios

For Teachers 9th - 12th Standards
Young scholars identify the different angles and sides of a triangle. In this geometry instructional activity, students identify the six trigonometric ratios. They graph the graph of each trig function and analyze it.
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Worksheet
Curated OER

Similar Polygons

For Students 10th
In this similar polygons worksheet, 10th graders solve and complete 20 various types of problems. First, they solve each proportion. Then, students write a ratio expressing the slope of a line through each pair of points. In addition,...
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Lesson Plan
Curated OER

Ratios of Similar Figures

For Teachers 9th - 12th Standards
Students identify the ratios of different triangles. For this geometry lesson, students identify the similarity and differences of triangles. They use the navigator to move the sides of the triangle around.
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Interactive
Curated OER

Similar Figures

For Students 7th - 10th
In this similar figures worksheet, students identify the meaning of similar, corresponding sides, and congruent.  They use proportions to find the length of a missing side.  Students dilate given figures according to a scale factor. ...
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Worksheet
Curated OER

The Triangles Problem

For Students 10th
In this geometry worksheet, 10th graders explain how two triangles can have 5 parts of the other triangle and still not be congruent. This is a word problem with an answer key.
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Worksheet
Houghton Mifflin Harcourt

Similar Polygons and Circles

For Students 9th - 12th
In these similar polygons and circles worksheets, students complete 15 questions including 9 word problems regarding similar polygons. Students then complete 15 questions including 1 word problem involving circumference, area, and arc...
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Lesson Plan
Curated OER

Investigating Trigonometric Ratios Through Similar Right Triangles

For Teachers 9th - 10th
Students identify similar and congruent right triangles. In this geometry activity, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.
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Lesson Plan
Curated OER

Congruent and Similar figures

For Teachers 8th
Eighth graders explore congruent and similar figures.  In this eighth grade geometry lesson, 8th graders use geoboards to create congruent and similar figures and explore the relationships between the sides and angles. 
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Worksheet
Curated OER

Similar Right Triangles-Introductions to Trigonometry

For Students 9th - 10th
In this geometry learning exercise, 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...
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Lesson Plan
Curated OER

Similarity and Congruence

For Teachers 9th - 12th
Students explore the concept of similarity and congruence. In this similarity and congruence instructional activity, students cut out strips of paper and form a triangle. Students try to prove that their triangles are congruent using the...
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Lesson Plan
Curated OER

Similar Triangles - Geometry Exploration

For Teachers 8th
Eighth graders become engaged in a lesson in geometry to improve mathematical skills. They construct triangles, segments, and points using Geometer's Sketchpad to demonstrate how dilations of triangles and rectangles change geometric...
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Lesson Plan
Curated OER

Similarity

For Teachers 6th - 8th
Students engage in a instructional activity that is concerned with the concept of similarity. This takes higher order thinking skills and being able to separate into categories. Specifically in this instructional activity they are...
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Worksheet
Curated OER

Exploring Similar Polygons

For Students 10th
In this exploring similar polygons learning exercise, 10th graders solve 9 various types of problems related to determining whether each polygon is similar or not. First, they write 3 equal ratios to show corresponding sides are...
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Lesson Plan
Curated OER

Geography: Lengths, Perimeter, and Area of Similar Objects

For Teachers 6th
Sixth graders explore characteristics of similar objects. Using attribute blocks, they explore the ratios of the perimeter, area and side length in similar shapes. They calculate and compare the area of shapes.
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Worksheet
Curated OER

Similar Figures

For Students 4th - 5th
In this similar figures worksheet, students determine area and perimeter of rectangles and triangles, then explain their thinking. Answers included on page 2.
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Lesson Plan
Curated OER

Fractals Teachers' Notes

For Teachers 5th - 8th
When you see a flower or a tree in nature do you see the math? This web resource contains many ideas for using fractals in a math class including Sierpinski’s triangle, Koch's Snowflake, and the Jurassic Park Fractal. Additionally, it...
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Lesson Plan
Futures Channel

Folding Circles

For Teachers 7th - 12th Standards
Students investigate properties of circles. In this geometry lesson, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
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Lesson Plan
Curated OER

Can a Geometric Mean be Nice?

For Teachers 11th - 12th
In this Geometry instructional (work)sheet, students are instructed on how to find the geometric mean.  Students are then shown how the geometric mean is applied to proving similar triangles.
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Lesson Plan
Curated OER

How Tall Is That Flag Pole?

For Teachers 6th - 8th
Students examine various triangles and discuss how similar triangles have sides that are proportional. They utilize an ancient Egyptian method to determine the height of a flagpole.
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Worksheet
Curated OER

Unit 5: Worksheet 4 - Proportion

For Students 8th - 10th
In this proportion worksheet, students use proportions to find the length of a missing side of similar triangles. They find percent of a number, and solve real life story problems with percents and discounts. This two-page worksheet...
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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

Similar Figures

For Students 7th - 9th
In this similar figures instructional activity, learners identify corresponding sides and corresponding angles of given polygons.  They identify similar figures.  This three-page instructional activity contains 18 problems.
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Lesson Plan
Curated OER

Triangles with Collinear Circumcenters

For Teachers 9th - 10th
Students identify the circumcenter of a triangle. In this geometry lesson, students construct a perpendicular bisector using a straight edge and a compass. They differentiate between triangles and collinear points.