Transversal Lines and Angles
Identifying the angles created by a transversal line. Finding the missing angles of a triangle or quadrilateral using the angle sum property. Finding the missing angle in a polygon. Applying the concept of interior and exterior angles. Applying the concept of similar triangles to find missing dimensions of polygons.
Mapped to CCSS Section# 8.G.A.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.