# Rhombus

A rhombus is an equilateral quadrilateral, which is a polygon having four sides of equal length.

A square is a special case of a rhombus where all four interior angles are ninety degrees.

In non-academic contexts, the term diamond can be applied to a rhombus, particularly if it is oriented with one of its diagonals vertical.[1]

Its area is the product of its diagonals divided by two. Note that its diagonals are perpendicular to each other, and bisect each other.

In symbolic form, the area of a rhombus having diagonals of lengths D1 and D2 is:

$A=\frac{D_1 \times D_2}{2}$

This area also equals the length of a side (B) multiplied by the length of the perpendicular between two opposite sides (H):

$A=B \times H$

## References

1. http://www.merriam-webster.com/dictionary/diamond sense 3