Properties
- Rhombuses belong to the class of parallelograms; they are parallelograms with four congruent sides.
 - The two diagonals of a rhombus are perpendicular.
 - The opposite sides of a rhombus are parallel.
 - A rhombus has two axes of symmetry.
 
Based on its properties, a rhombus belongs to the family of convex quadrilaterals, trapezoids and parallelograms.
Formulas
The perimeter P of a rhombus with side length c is given by : \(P=4c\).
The area A of a rhombus with a short diagonal \(d\) and a long diagonal \(D\) is given by : \(A=frac{Dtimes d}{2}\)