Lesson plan

Prove and apply the conjecture that two transversals cutting through three or more parallel lines are divided proportionally

teaches Common Core State Standards CCSS.Math.Content.HSG-SRT.B.4 http://corestandards.org/Math/Content/HSG/SRT/B/4
teaches Common Core State Standards CCSS.Math.Practice.MP1 http://corestandards.org/Math/Practice/MP1
teaches Common Core State Standards CCSS.Math.Practice.MP3 http://corestandards.org/Math/Practice/MP3

You have saved this lesson plan!

Here's where you can access your saved items.

Content placeholder

or to view additional materials

You'll gain access to interventions, extensions, task implementation guides, and more for this lesson plan.

Big Ideas: We can use similarity to prove theorems that extend from triangles. Proportional segments of transversals prove line segments are parallel. The tasks in this lesson require students to show that a line is parallel to the third side of a triangle if it creates segments of the other two sides that are proportional. Students will use prior knowledge of parallel lines, similarity, and the AA similarity criteria to prove the proportion. This lesson leads into solving problems involving similar triangles and right triangle trigonometry. Vocabulary: Similarity Proportionality