Examine the information provided in each diagram below. Decide if each figure is possible or not. If the figure is not possible, explain why.  

1. 

   Hint (a):

   What angle measure is supplementary to $120^\circ$?
   Would this also satisfy the Triangle Angle Sum Theorem?

2. 

   Hint (b):

   How are the same-side interior angles in a parallelogram related?

3. 

   Hint (c):

   Are the vertical angles equal?