This resource is a guided notes set about determining the value of angles of triangles and triangle exterior angle theorem. Topics include finding the measure of a missing value in a triangle, finding missing values in a larger set of triangles, finding the missing angle value in a triangle given an exterior angle, and determine the exterior angle value based on values inside the triangle.

The guided notes set is two pages and includes a check or a you try question(s) that students should do on their own. The answer key to the guided notes is included.