Square, Rectangle and Parallelogram

To define a square it must have equal sides, and internal angles equal to 90º To define a rectangles all internal angles must be 90º, not needing equal sides To define a parallelogram the sides must be parallel.

Area equals base multiplied by height

letter	value
A	Area
B	Base
h	Height

In the case of parallelogram the height is the segment perpendicular to the base, so that the two form an angle of 90º