A rhombus is an equilateral parallelogram with four equal sides and diagonals that are perpendicular bisectors of each other. Key properties include having two sets of congruent isosceles triangles formed by its diagonals, interior and exterior angles that sum to 360 degrees, and an area calculated as half the product of its two diagonals or as base times altitude.

2.  Singular: Rhombus
 Plural: Rhombi
 A rhombus is an equilateral parallelogram
(quadrilateral) -a polygon with four equal sides
in length
 Other terms for a rhombus is a diamond or
lozenge

3.  Diagonals of a rhombus are perpendicular bisectors
to each other
 Interior and exterior angles equal to 360 degrees
 All sides are congruent
 rhombus forms two congruent isosceles triangles
 Consecutive angles are supplementary

4.  The diagonals of a rhombus forms a right
triangle

5.  Base: Any side of the rhombus can be considered a
base
 Altitude: The perpendicular distance from the base to
the opposite side
 Area: The product of both diagonals divided by 2
(D1 x D2)/2
 Common area: (base x altitude)
 Perimeter: The distance around the rhombus (sum of
the lengths)

6. DIAGRAM OF TWO RHOMBI RHOMBIC TILING

7. DIAGRAM OF TWO RHOMBI RHOMBIC TILING