Willow Tree
Ratios and Proportions with Congruent and Similar Polygons
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...
Virginia Department of Education
Similar Figures
How similar do figures have to be to be similar figures? Individuals learn to identify similar figures by verifying that angles are congruent and sides are proportional. Additionally, they match the corresponding parts of similar figures.
Curated OER
Dihedral Figures
Middle and high schoolers perform transformations. In this web based lesson, students explore dihedral figures. They use the web tools to translate, rotate, and reflect figures. Pupils identify lines of symmetry.
Curated OER
Understanding Proportions and Scale Drawings
Proportions are ratios found using multiplication or division. Middle schoolers solve measurement problems, find a figure's missing dimension, and find the distance between two points. Resource features four lesson plans with detailed...
Curated OER
Identify Similar Figures
Students explore the concept of similar figures. In this similar figures instructional activity, students develop the idea that similar figures are a different size but the same shape by comparing similar rectangles. Students use patty...
Virginia Department of Education
Similar Triangles
Pupils work in pairs to investigate what it takes to prove that two triangles are similar. They work through various shortcuts to find which are enough to show a similarity relationship between the triangles. Small groups work with the...
Curated OER
Proportionality Using Labyrinths and Mazes
Conduct research on the Internet about labyrinths and mazes to learn about proportions and ratios. Inquisitive minds design their own maze, one maze is chosen and proportionately enlarged to 20 feet by 30 feet. This is a fun challenge...
Curated OER
Similarity
Eighth graders understand that proportional enlargement of shapes doesn't change the angles of those shapes. In this similarity lesson plan, 8th graders complete exercises to create enlargements of shapes and understand similar shapes.
EngageNY
Between-Figure and Within-Figure Ratios
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...
Virginia Department of Education
Similar Solids and Proportional Reasoning
Double the dimensions, quadruple the surface area. Pairs build similar prisms and compare the ratios of their surface areas and volumes to the ratio of the heights. Given two similar cones, partners determine the ratios of the lateral...
EngageNY
Special Relationships Within Right Triangles—Dividing into Two Similar Sub-Triangles
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...
Curated OER
Similarity
Students find the factor of proportionality in similar polygons. For this similarity of polygons lesson plan, students measure the sides and angles of polygons and derive a factor of proportionality between corresponding pairs of sides...
Utah Education Network (UEN)
Finding Missing Lengths of Similar Triangles
Middle and high schoolers explore the properties of similar triangles. In this geometry lesson, pupils play a similarity basketball game, sketch similar triangles, and find the missing measures of similar figures. They find the height of...
Curated OER
Similar Triangles and Proportions
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.
Curated OER
Indirect Measurement with Similar Triangles
Students use similar triangles to find missing heights. In this using similar triangles to find missing heights instructional activity, students use proportions to find the heights of missing side lengths. Students find the height of...
Curated OER
Measurement of Objects Using Similar Triangles in The Plane
Students use similar triangles and a sight tool to find the height and distance between large objects. In this similar triangles lesson plan, students use a constructed sight tool to measure the distance and height of an object using an...
Curated OER
Similarity and Congruence
Students explore the concept of similarity and congruence. In this similarity and congruence activity, students identify and verify whether or not two figures are similar, congruent, or neither. Students use postulates and theorems such...
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...
Curated OER
Applying Proportionality in Scale Drawings
Sixth graders examine a blue print and discuss the reasoning behind using blue prints. In this proportionality lesson, students collaborate with their teammates to create a scale drawing. Once that is complete, 6th graders write a...
Curated OER
Proportionality Using Wind in the Willows
Students examine proportionality in Wind in the Willows by comparing Mr. Toad, objects proportional to him and objects proportional to humans. They then measure a stuffed Mr. Toad and make common objects proportional to Mr. Toad???s...
Pace University
Grades 7-8 Solving Equations
Create a similar blueprint. The differentiated lesson has pupils work in teams to create a brochure, scale model, or blueprint of a selected house with some minor changes. Once finished, team members present their final projects to the...
EngageNY
Linear Equations in Disguise
In the eighth segment of a 33-part unit, learners look at equations that do not appear to be linear at first glance. The equations are proportions where the numerators and denominators may have more than one term. To round out the...
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.