What is another (more descriptive) name for each polygon described below?

1. A regular polygon with an exterior angle measuring $120º$.

   Answer (a):

   equilateral triangle

2. A quadrilateral with four equal angles.

   Answer (b):

   rectangle because all angles would be $90º$.

3. A polygon with an interior angle sum of $1260º$.

4. A quadrilateral with diagonals that are perpendicular bisectors of each other.