G.CO.9 Prove parallel lines

This applet is designed to help you discover relationships of angles created when a transversal line crosses parallel lines. The angle relationships include vertical, corresponding, alternate and linear pairs.
Where are vertical angles? What are their angle measures? Where are linear pairs? What are their angle measures? What is their sum? Where are corresponding angles? What are their angle measures? Where are alternate angles? What are their angle measures? How many supplementary pairs can you find?