Properties of
rhombuses, rectangles & squares
As you can see from the above Venn diagram, Squares, Rectangles and Rhombuses are all Parallelograms because they all have opposite sides that are parallel. A Rectangle can be a square, a Rhombus can be a Square but a Square can never be a Rectangle or a Rhombus. The theorems below explain why and when the above figures are parallelograms.