Cuemath
Cuemath: What Is Similarity?
This mini-lesson introduces the properties of similarity and its role in geometry.
Texas Education Agency
Texas Gateway: Generalizing Geometric Properties of Ratios in Similar Figures
Students will investigate patterns to make conjectures about geometric relationships and apply the definition of similarity, in terms of a dilation, to identify similar figures and their proportional sides and congruent corresponding...
CK-12 Foundation
Ck 12: Geometry: Corresponding Parts of Congruent Figures
[Free Registration/Login may be required to access all resource tools.] In this lesson, students identify corresponding parts of congruent figures. They examine guided notes, review guided practice, watch instructional videos, and...
Sonoma State University
Sonoma State University: Parallel Lines and Similar and Congruent Triangles
This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.
Texas Instruments
Texas Instruments: Similar Figures Discovery Activity
Students can use Cabri Jr. to discover two properties of similar triangles: corresponding angles are congruent and corresponding sides are proportional.
Khan Academy
Khan Academy: Similarity and Transformations
Given two polygons, try to map one onto the other using angle-preserving transformations, and determine whether they are similar. Transformations are done in "intuitive mode." Students receive immediate feedback and have the opportunity...
CK-12 Foundation
Ck 12: Geometry: Similar Polygons and Scale Factors
[Free Registration/Login may be required to access all resource tools.] This concept teaches students what similar polygons are and how to use scale factors to solve for missing information in similar polygons.
Khan Academy
Khan Academy: Use Similar & Congruent Triangles
Solve geometry problems with various polygons by using all you know about similarity and congruence.
Illustrative Mathematics
Illustrative Mathematics: 8.g, G Gpe, G Srt, G Co Is This a Rectangle?
For this task, students are given four sets of coordinate pairs and are asked to determine if they represent a rectangle. Aligns with 8.G.A, 8.G.B, G-CO.B, G-GPE.B, and G-SRT.B.5.
CK-12 Foundation
Ck 12: Geometry: Corresponding Parts of Similar Figures
[Free Registration/Login may be required to access all resource tools.] In this lesson, students identify corresponding parts of similar figures. Students examine guided notes, review guided practice, watch instructional videos and...
Varsity Tutors
Varsity Tutors: Hotmath: Similar Figures
Find a clear explanation of similar figures. Discusses how they can be transformed through a sequence of rotations, reflections, translations, and dilations. Explanations are supported with illustrated examples.
Geometry Help
Geometry Help: Similar Triangles
Explains the basic concept of similar triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
CK-12 Foundation
Ck 12: Interactive Geometry: 6.7 Applications of Similar Triangles
Learn how similar triangles have congruent corresponding angles and proportional corresponding sides.
CK-12 Foundation
Ck 12: Interactive Geometry: 6.5 Sss Triangle Similarity
Explore and understand two triangles that are similar.
CK-12 Foundation
Ck 12: Interactive Geometry: 6.4 Sas Triangle Similarity
Explore and understand triangle similarity.
Sophia Learning
Sophia: Similarity
This learning tutorial describes the characteristics of similar figures and how to use scale factor and proportions to determine missing side lengths. The lesson includes PowerPoint presentations and videos demonstrating how to solve...
Illustrative Mathematics
Illustrative Mathematics: G Srt Folding a Square Into Thirds
The goal of this task is to apply knowledge about similar triangles in order to understand an origami construction: trisection of the side of a square. Aligns with G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Srt Bank Shot
This task asks students to use similarity to solve a pool table problem. Students must use the fact from physics that when an object bounces off of a wall, the angle of incidence equals the angle of reflection. Aligns with G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Gpe, G Srt Slope Criterion for Perpendicular Lines
The goal of this task is to use similar triangles to establish the slope criterion for perpendicular lines. Aligns with HSG-GPE.B.5 and HSG-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Srt Tangent Line to Two Circles
The purpose of this task is to use similar triangles and setting up a proportion in order to calculate a side length. Aligns with G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Srt Extensions, Bisections, Dissections in Rectangle
For this task, learners must draw a diagram from a verbal description and use their understanding of similar triangles to find the area of a quadrilateral. Aligns with G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G Gpe, G Srt Finding Triangle Coordinates
Given a picture of a triangle on a coordinate grid, students are asked to find the coordinates of points which divide line segments in a given ratio. Aligns with G-GPE.B.6 and G-SRT.B.5.
Math Open Reference
Math Open Reference: Similar Triangles
Learn about similar triangles with this helpful reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Shodor Education Foundation
Shodor Interactivate: Lesson: Translations, Reflections, and Rotations
This upper elementary and middle school lesson plan introduces a variety of motion geometry concepts such as translations, reflections, and rotations. Lots of interactive support for students.