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
Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams Lesson PlanSimilar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams Lesson Plan
Publisher
EngageNY
Resource Details
Curator Rating
Educator Rating
Not yet Rated
Grade
9th - 12th
Subjects
Math
2 more...
Resource Types
Lesson Plans
5 more...
Audience
For Teacher Use
Duration
45 mins
Instructional Strategies
Guided Practice
1 more...
Language
English, Arabic
Lesson Plan

Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams

Curated and Reviewed by Lesson Planet
This Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams lesson plan also includes:
  • Geometry Module 5: Teacher Materials
  • Geometry Module 5: Student Materials
  • Geometry Module 5: Copy Ready Materials
  • Geometry Module 5, Topic C Overview
  • Geometry Module 5, Topic C, Lesson 16: Teacher Version (Doc)
  • Geometry Module 5, Topic C, Lesson 16: Student Version (PDF)
  • Geometry Module 5, Topic C, Lesson 16: Student Version (Doc)
  • Join to access all included materials

First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a circle to develop relationships. Learners then prove these relationships.

4 Views 3 Downloads
CCSS: Designed

Concepts

similar triangles, circles, secant, tangent lines

Additional Tags

math

Instructional Ideas

  • Consider modifying the lesson to extend it to two days, as there are multiple theorems to cover

Classroom Considerations

  • Exploratory challenges require a ruler
  • Proofs require knowledge of similar triangles
  • The 17th installment of a 23-part module

Pros

  • Exploratory challenges keep learners engaged in the subject material
  • Learners develop their own formulas through investigation rather than being told the correct formula

Cons

  • The relationship for secants intersecting exterior to the circle is more commonly expressed using the whole secants and the external segments rather than the internal segments and external segments as in the lesson

Common Core

HSG-C.A.2

View 41,189 other resources for 9th - 12th Grade Math

© 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