Finding Missing Angles in Triangles

In geometry, the Triangle Angle-Sum Theorem states that the measures of the interior angles of a triangle add up to 180 degrees. This eighth-grade math worksheet will introduce students to this theorem and model how to find a missing interior angle in a triangle. Then learners are challenged to apply this concept as they practice finding missing angles in triangles across two pages of practice problems. As an added challenge, have students complete the Interior Angles in Triangles: Solve for the Variable worksheet next!