Unit Plan
Texas Education Agency

Texas Gateway: Generalizing Geometric Properties of Ratios in Similar Figures

For Students 9th - 10th Standards
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...
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.3 Aa Triangle Similarity

For Students 9th - 10th Standards
If two triangles are similar, it means that all corresponding angle pairs are congruent and all corresponding sides are proportional. However, in order to be sure that two triangles are similar, you do not necessarily need to have...
Lesson Plan
Other

Nearpod: Similar Figures & Proportionality

For Teachers 9th - 10th
In this lesson plan on similar figures and proportionality, students explore how to identify if figures are similar by applying their knowledge of corresponding angles and sides.
Activity
Texas Instruments

Texas Instruments: Similar Figures Discovery Activity

For Teachers 9th - 10th Standards
Students can use Cabri Jr. to discover two properties of similar triangles: corresponding angles are congruent and corresponding sides are proportional.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.7 Applications of Similar Triangles

For Students 9th - 10th Standards
Learn how similar triangles have congruent corresponding angles and proportional corresponding sides.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.5 Sss Triangle Similarity

For Students 9th - 10th Standards
Explore and understand two triangles that are similar.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.4 Sas Triangle Similarity

For Students 9th - 10th Standards
Explore and understand triangle similarity.
Unit Plan
Sophia Learning

Sophia: Similarity

For Students 9th - 10th Standards
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...
Lesson Plan
Science and Mathematics Initiative for Learning Enhancement (SMILE)

Smile: Similarity

For Teachers 9th - 10th Standards
This site contains a lesson plan for high school age students. The objective is to discover the factor of proportionality in similar polygons and to relate this factor to the perimeters and areas of similar polygons.
Handout
Sonoma State University

Sonoma State University: Parallel Lines and Similar and Congruent Triangles

For Students 9th - 10th Standards
This site defines eleven theorems relating to parallel lines and similar and congruent triangles. Links to the theorems and relevant term descriptions are provided.
PPT
Sophia Learning

Sophia: Corresponding Parts: Lesson 5

For Students 9th - 10th Standards
This lesson will define the phrase corresponding parts (e.g. angles, sides, etc.). It is 5 of 5 in the series titled "Corresponding Parts."
Handout
Sonoma State University

Sonoma State University: Parallel Lines and Similar and Congruent Triangles

For Students 9th - 10th Standards
This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.
Activity
Texas Instruments

Texas Instruments: Math Today Ballooning Inside the Box

For Teachers 9th - 10th Standards
In this activity Using the USATODAY infograph, "Ballooning inside the box", students will explore geometric relationships using similar triangles. Identifying triangles with two pairs of congruent angles to explore similarity properties...