Everyday Mathematics
Mathematics Within: Slope and Triangles
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
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.
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.
Mathematics Vision Project
Similarity and Right Triangle Trigonometry
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
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
Corresponding Parts of Similar Triangles
Here is a lesson that has learners take a look at corresponding parts of similar triangles, ratios of similarity, reductions and enlargements. They'll manipulate the scale factor (r) to observe the changes in similar triangles and then...
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
Zome System
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...
Curated OER
Similar Triangles
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.
Curated OER
Similar Triangles - Applied Problems
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.
Curated OER
Triangle Series
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.
Curated OER
Similarity and Dilations - Discover Properties of Similar Figures
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...
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...
101 Questions
Square Partitions
Challenge your classes while developing their problem-solving skills. A square is divided neatly into four equal triangles by its diagonals until one diagonal is moved from a vertex to the midpoint of one side. Now, scholars must devise...
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
Similar Figures
Your class will use a TI calculator to drag vertices of rectangles and triangles to observe what happens to ratios of pairs of sides within each figure. They will apply the definition of similarity to identify similar shapes. The...
Curated OER
Similar triangles
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
Curated OER
Finding Area of Similar Figures
Students explore the concept of finding area of similar figures. In this finding area of similar figures lesson, students use pattern blocks to construct similar figures. Students trace their construction and find the area. Students...
Curated OER
II Similar
Pupils, through lecture and guided practice, discover the properties of similar triangles. They use given measurements of one triangle to find a missing measurement of a similar triangle. They apply this knowledge in real-life...
Curated OER
Similar Triangles on the Coordinate Plane
Young scholars investigate triangles and their properties. In this geometry lesson plan, students differentiate between similar and congruent triangles. They use the SSS theorem to help identify the triangles that are similar or congruent.
Utah Education Network (UEN)
Finding Slope of a Line from Graphs, Tables, and Ordered Pairs
Middle schoolers explore the concept of slope in numerous ways and start to look at simple linear equations. They describe the slope in a variety of ways such as the steepness of a line, developing a ratio, using graphs, using similar...
Curated OER
Angles and Similarity
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...
Curated OER
Trigonometry Ratios
Learners identify the different angles and sides of a triangle. In this geometry lesson, students identify the six trigonometric ratios. They graph the graph of each trig function and analyze it.
Curated OER
Ratios of Similar Figures
Students 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.