EngageNY
Similarity
Learn similarity through a transformations lens! Individuals examine the effects of transformations and analyze the properties of similarity, and conclude that any image that can be created through transformations is similar. The...
EngageNY
The Side-Angle-Side (SAS) and Side-Side-Side (SSS) Criteria for Two Triangles to Be Similar
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...
Education Development Center
Similar Triangles
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.
Illustrative Mathematics
Right Triangles Inscribed in Circles I
One of the basic properties of inscribed angles gets a triangle proof treatment in a short but detailed exercise. Leading directions take the learner through identifying characteristics of a circle and how they relate to angles and...
Mathematics Assessment Project
Solving Problems with Circles and Triangles
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.
Curated OER
Symmetry, Similar & Congruent Shapes
Fifth graders identify lines of symmetry., similar and congruent shapes. They use construction paper to create their own symmetrical shapes. Students create stained glass frames containing symmetrical, congruent and similar shapes.
Utah Education Network (UEN)
It's All Just Similar to Me
Middle schoolers explore the concept of similar figures. In this similar figures lesson, pupils calculate scale factors of similar triangles. They find missing sides of triangles, and measure angles using protractors and measure sides of...
Curated OER
Proportions 1
In this proportion worksheet, students find the missing side of 4 shapes that are similar to their mate. Shapes include triangles and quadrilaterals,. In the second part of the worksheet, students use the scale factor to find missing...
Curated OER
When Does SSA Work to Determine Triangle Congruence?
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.
EngageNY
End-of-Module Assessment Task: Grade 7 Mathematics Module 6
Determine the level of understanding within your classes using a summative assessment. As the final lesson in a 29-part module, the goal is to assess the topics addressed during the unit. Concepts range from linear angle relationships,...
El Paso Community College
Geometry Definitions
Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet.
Curated OER
Similarity and Congruence
Students determine that two figures are similar or congruent by
investigating figures that are similar and figures that are congruent. They prove that two figures are similar or congruent by using definitions,
postulates, and theorems.
Futures Channel
Folding Circles
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.
Curated OER
Geography: Lengths, Perimeter, and Area of Similar Objects
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.
Concord Consortium
Proportional Representation
Sometimes the solution is all a matter of perspective. The short assessment task presents a problem to pupils that requires them to make sense of a diagram. Once learners see two similar triangles, the rest of the solution is solving a...
Curated OER
The Truth About Triangles And Proofs
Students engage in a lesson plan that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the...
Helping with Math
Geometry: Areas of Triangles
For this areas of triangles instructional activity, students observe given polygons. They determine the area of triangles, rectangles and compound figures. This one-page instructional activity contains 5 multi-step problems. This...
Curated OER
Toothpick Triangles
Explore patterns, variables, and mathematical relationships when you examine patterns with toothpicks and determine the next sequence of figures. Your class writes and justifies a formula based on the sequence. An answer key is included.
Curated OER
Soda Cans
Students identify and use properties of similar figures. In this geometry lesson, students use proportions of the sides of triangles to solve triangular relationships. They use soda can as their visuals.
Curated OER
Symmetry and Geometric Shapes on Campus
Build on your learners' previous knowledge of geometric shapes and symmetrical figures. Then set them out to take photos of geometric shapes on campus. They assess whether the photos contain symmetry or not.
Curated OER
Fractals Teachers' Notes
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...
Discovery Education
Discovering Math: Exploring Geometry
Apply geometric properties and formulae for surface area and volume by constructing a three-dimensional model of a city. Learners use similar and congruent figures and transformations to create a city of at least 10 buildings. They trade...
Curated OER
Similar Triangles
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.
Curated OER
Similarity and Congruence
Students explore the concept of similarity and congruence. In this similarity and congruence lesson plan, students cut out strips of paper and form a triangle. Students try to prove that their triangles are congruent using the SSS...