6 people have favorited this lesson!
8.G.5 Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
Log in to view this lesson. If you do not have an account, subscribe now and begin your free 30 day trial.
Concept Development - Geometry