Alternate Interior Angles Theorem (V2)

In the applet below, a TRANSVERSAL intersects 2 PARALLEL LINES.  When this happens, there are 2 pairs of ALTERNATE INTERIOR ANGLES that are formed.  Interact with the applet below for a few minutes, then answer the questions that immediately follow.
Directions & Questions:  1) Complete the following statement: If a transversal intersects 2 ________________  ______________, then alternate interior angles are _____________________.  2) If the pink angle above measures 156 degrees, what would the measure of its alternate interior angle be?  What would the measure of the gray angle be?   3) As you moved the slider, what transformation(s) took place?