Explore the world of the angle sum theorem in this mini-lesson. Provides a definition and solved examples that help with understanding their properties. Includes practice questions with answers.

In this task, 8th graders have to reason with angles and angle measurements, including the sum of the angles in a triangle, to deduce information from a picture. Includes a GeoGebra worksheet that the teacher can use for demonstration...

In this task, 8th graders are presented with a drawing of two parallel lines connected through two line segments. They are given the measures of two angles and are asked to find a third. Aligns with 8.G.A.5.

This tutorial discusses exterior angles of a triangle. Example problems with explanations are included.

This geometry lesson defines equilateral, isosceles, and scalene triangles, and has a variety of exercises, including drawing exercises.