Lesson Plan
Curated OER

Similar Triangles on the Coordinate Plane

For Teachers 9th - 10th
Students investigate triangles and their properties. In this geometry lesson, students differentiate between similar and congruent triangles. They use the SSS theorem to help identify the triangles that are similar or congruent.
Worksheet
Curated OER

Exploring Similar Figures

For Students 10th
In this similar figures worksheet, 10th graders solve and measure 10 different angles that are similar. First, they determine which angel corresponds to each given angle. Then, students determine the scale factor of a particular...
Lesson Plan
Curated OER

Angles and Similarity

For Teachers 9th - 12th Standards
High schoolers 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...
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...
Lesson Plan
Curated OER

Ratios of Similar Figures

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

Quiz: Similarity

For Students 7th - 8th
For this similarity worksheet, students use the characteristics of similar figures to determine the length of one side of a polygon, the height of a tree, or the shortest side of a triangle. They also identify similar figures. ...
Interactive
National Council of Teachers of Mathematics

Scale Factor

For Students 6th - 12th Standards
Does doubling mean everything doubles? Learners adjust the scale factor between two rectangles. Using the calculated measurements, pupils investigate the ratios between the lengths, perimeters, and areas of the rectangles.
Worksheet
Curated OER

Similar Polygons

For Students 10th
For 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,...
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...
Worksheet
Curated OER

The Triangles Problem

For Students 10th
For 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.
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...
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 lesson, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.
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. 
Unit Plan
Radford University

2 and 3 Dimensional Shapes

For Students 9th - 12th Standards
Take a similar approach to three dimensions. Pupils develop the relationship between areas of similar objects and see how they relate to the ratio of the sides. Building upon area formulas, small groups put together volume formulas for...
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...
Lesson Plan
Curated OER

Similarity and Congruence

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

Similar Triangles - Geometry Exploration

For Teachers 8th
Eighth graders become engaged in a activity 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...
Lesson Plan
Curated OER

Similarity

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

Exploring Similar Polygons

For Students 10th
In this exploring similar polygons worksheet, 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 proportional to...
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.
Worksheet
Curated OER

Similar Figures

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

Folding Circles

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