Math: Geometry: Similarity and Congruence
These web sites are about the geometric concepts of similarity and congruence. Learn about postulates and theorems related to these concepts, and practice proving similarity or congruence. There are tutorials, quizzes, interactive features, printable worksheets, and lesson plan ideas.
Relations and Sizes: Similar Figures
Click through this short lesson to read an overview of similarity, see examples, and take a practice quiz. NOTE: This site contains ads.
Relations and Sizes: Congruent Figures
Click through this short lesson to read an overview of congruence, see examples, and take a practice quiz. NOTE: This site contains ads.
ThinkQuest: Congruent Triangles
This page explains and defines congruent triangles and provides examples. There is a review quiz at the bottom of the page.
ThinkQuest: Similar Polygons
This page explains and defines similar polygons and provides examples. When you are finished reading, you can take the quiz.
BBC: Congruent and Similar Shapes
Click through this tutorial on similar or congruent shapes, how to prove congruence, and how to calculate similar areas or volumes. When you have read all of the pages you can take a review test. NOTE: The site includes ads and leads to a discussion board.
Investigate the properties of similar triangles with these interactive sketches. Click on "Condensed Lessons" or "Practice Your Skills" to see printable PDF files with more information and exercises.
Congruent and Similar Shapes
Here is a PowerPoint slide show that explains congruence, similarity, and scale factors, with examples.
Lesson Plan: Proving Triangles are Similar and Congruent
In this lesson, students can learn the formal proofs for proving whether triangles are similar or congruent or not.
Construct a Similar Polygon
Practice constructing similar polygons using this interactive graphics feature.
Lesson Plan: Similarity and Congruency
This lesson plan includes several activities on congruent and similar triangles. The page provides teachers with a prediction guide as students' warm-up exercises before the activities, worksheets with keys, and helpful guidelines.
Discovering Congruent Triangles Activity
This seven-page Microsoft Word document is a lesson plan based on hands-on activities that involve group of students to construct various congruent triangles.
Quia: Triangle Congruence and Similarity #1
Play the game and brush up on what you learned about congruent and similar triangles.
BrainPOP: Similar Figures
Watch an animated movie with Tim and Moby and find out how similar triangles are used for indirect measurements. NOTE: Site available by subscription only.