Lesson Planet
Search educational resources
  • Sign In Try It Free
  • AI Teacher Tools
    • Discover Resources Search reviewed educational resources by keyword, subject, grade, type, and more
    • Curriculum Manager (My Content) Manage saved and uploaded resources and folders To Access the Curriculum Manager Sign In or Join Now
    • Browse Resource Directory Browse educational resources by subject and topic
    • Curriculum Calendar Explore curriculum resources by date
    • Lesson Planning Articles Timely and inspiring teaching ideas that you can apply in your classroom
    • Our Story
    • Frequently Asked Questions
    • Testimonials
    • Contact Us
  • Pricing
  • School Access
    • Your school or district can sign up for Lesson Planet — with no cost to teachers
      Learn More
  • Sign In
  • Try It Free

Hi, what do you want to do?

Create a lesson plan
Create a lesson plan
Generate resources with 80+ AI teacher tools
Generate resources with 80+ AI teacher tools
Search 200,000 instructional videos
Search 200,000 instructional videos
Find a teaching resource
Find a teaching resource
Khan Academy: Geometry: Similar Triangles Instructional VideoKhan Academy: Geometry: Similar Triangles Instructional Video
Publisher
Khan Academy
Resource Details
Curator Rating
Educator Rating
Not yet Rated
Grade
9th - 10th
Subjects
Math
1 more...
Resource Type
Instructional Videos
Audiences
For Administrator Use
2 more...
Lexile Measures
0L
Instructional Video

Khan Academy: Geometry: Similar Triangles

Curated by ACT

Explains how to determine unknown side lengths of similar triangles by identifying corresponding sides and angles ans setting up proportions. The first example is a continuation from the video "Similar Triangles." Practice problems available. [9:55]

3 Views 0 Downloads
CCSS: Adaptable

Concepts

corresponding angles, corresponding sides, similar triangles

Additional Tags

determining unknown side lengths, proving triangle similarity

Classroom Considerations

  • Knovation Readability Score: 1 (1 low difficulty, 5 high difficulty)
  • The intended use for this resource is Instructional
  • This video is hosted on YouTube

Common Core

HSG-SRT.A.2 HSG-SRT.A.3 HSG-SRT.C.6

See similar resources:

Instructional Video

Similar Triangles, Similarity, Geometry

Khan Academy
Although a rather complicated topic, this video clearly explains the concept of solving problems involving similar triangles. It employs problem-solving to determine whether two figures are similar triangles. In addition, it provides...
10 mins 9th - 10th Math
Instructional Video

Similar Triangles (Part 2), Similarity, Geometry

Khan Academy
Building on concepts in the first part of the series on similar triangles, installment number two explores how to find the values for given angles in a triangle. These problems are solved by using algebra and ratios. A step-by-step...
10 mins 9th - 10th Math
Instructional Video

Khan Academy: Geometry: Similar Triangles

Khan Academy
Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals. [9:34]
9th - 10th Math
CCSS: Adaptable
Instructional Video

Khan Academy: Geometry: Similar Triangle Basics

Khan Academy
Explains the difference between congruent triangles and similar triangles. Introduces the idea of scale factors. [9:17]
9th - 10th Math
CCSS: Adaptable
Instructional Video

Khan Academy: Geometry: Similarity Example Where Same Side Plays Different Roles

Khan Academy
Explains how to determine unknown side lengths in a diagram that involves similar triangles where the two triangles share a side and the shared side corresponds to two different sides in each triangle. [6:05]
9th - 10th Math
CCSS: Adaptable
Unknown Type

Khan Academy: Solve Similar Triangles (Basic)

Khan Academy
Given two similar triangles and some of their side lengths, find a missing side length. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
9th - 10th Math
CCSS: Designed
Unknown Type

Khan Academy: Solve Similar Triangles (Advanced)

Khan Academy
Given two similar triangles and some of their side lengths, find a missing side length. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
9th - 10th Math
CCSS: Designed
Instructional Video

Khan Academy: Geometry: Similar Example Problems

Khan Academy
Explains how to identify and use similar triangles in order to determine unknown side lengths in two given diagrams. Each diagram also applies knowledge of angles formed when parallel lines are cut by a transversal. [7:37]
9th - 10th Math
CCSS: Adaptable
Unknown Type

Khan Academy: Solve Similar Triangles (Basic)

Khan Academy
Given two similar triangles and some of their side lengths, find a missing side length.
9th - 10th Math
CCSS: Adaptable
Instructional Video

Khan Academy: Geometry: Ca Geometry: More on Congruent and Similar Triangles

Khan Academy
Demonstrates solutions to problems #17-20 of California Geometry released state test questions. Problems address understanding of similar triangles, parallelograms and properties of the diagonals of parallelograms. [11:11]
9th - 10th Math
CCSS: Adaptable
Try It Free
© 1999-2026 Learning Explorer, Inc.
Teacher Lesson Plans, Worksheets and Resources

Sign up for the Lesson Planet Monthly Newsletter

Open Educational Resources (OER)

  • Health
  • Language Arts
  • Languages
  • Math
  • Physical Education
  • Science
  • Social Studies
  • Special Education
  • Visual and Performing Arts
View All Lesson Plans

Discover Resources

  • Our Review Process
  • How it Works
  • How to Search
  • Create a Collection

Manage Curriculum

  • Edit a Collection
  • Assign to Students
  • Manage My Content
Contact Us Site Map Privacy Policy Terms of Use