Your device is currently offline. You can view downloaded files in My Downloads.

Lesson Plan

Identify measurements for missing interior and exterior angles using informal arguments

teaches Common Core State Standards 111.28.8.D
teaches Common Core State Standards 111.41.5.A
teaches Common Core State Standards CCSS.Math.Content.8.G.A.5
teaches Common Core State Standards MAFS.8.G.1.5
Quick Assign

You have saved this lesson!

Here's where you can access your saved items.


Card of

or to view additional materials

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

Big Ideas: An exterior angle of a triangle is equal to the sum of the remote interior angles in relation to that exterior angle. Equivalence of angles can be represented in many ways. Students will look at multiple paths for finding the same angle measures. They will compare paths for finding exterior angles either by using the relationship between exterior and remote interior angles or by looking at the relationships formed with supplementary lines and the triangle angle sum. Students will use mathematical reasoning to justify their solutions. Students will draw on the relationship of supplementary angles learned in grade 7 as well as the triangle angle sum relationship from previous lessons in grade 8. Vocabulary: exterior angle of a triangle, remote interior angles of a triangle, supplementary, triangle angle sum
Provide feedback