**Course Page for Rebecca McDowell**

Parallel Lines and Transversals

Alternate Interior and Alternate Exterior Angles

This is designed to prove to students that alternate interior angles of two parallel lines cut by a transversal are equal. It is also designed to prove the same for alternate exterior angles of parallel lines cut by a transversal.

Below is a link to my Java Sketch. It can be used to explore alternate interior angles and alternate exterior angles.

Alternate Interior/Exterior Angles

__Instructions:__

Point B and Point D can either be manipulated by clicking and dragging them around the screen.

The top parallel line is j, the bottom parallel line is k, and the transversal line is l.

__Questions:__

- What do you notice about the angle measurements when you move Point D?
- What do you notice about the angle measurements when you move Point B?
- What conclusions can you draw from the commonalities and differences in the angle measure?