Alternate Interior Angles Theorem

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?