A rectangle is a four-sided figure with a right angle at each corner. A rhombus is a figure with four equal sides. A figure that is both a rectangle and a rhombus is a square.
They are both 4 sided quadrilaterals
a rectange
A parallelogram is any four-sided figure that has two pairs of parallel sides.A rhombus is any parallelogram with two adjacent equal sides. Any rhombus is a parallelogram.A square satisfies both of these definitions. Any square is just a rhombus with a right angle in it.
A quadrilateral can be both a rhombus and a parallelogram because they both have four sides.