No, but a parallelogram is a polygon.
Yes
2
paralellagram
Two (or none, if it is a rectangle).
It depends on what measure is missing.
Not normally unless it is in the shape of a rectangle.
Paralellagram
base times height is area
Paralellagram, Square or Rectangle
Yes, all sides and angles are equal and parallel.
It belongs in the class of quadrilaterals that all have 4 sides
They are all misspelled.