A lozenge is an equilateral parallelogram whose acute angles are 
. Sometimes, the restriction to 
is dropped, and it is required only that two opposite
angles are acute and the
other two obtuse. The term rhombus
is commonly used for an arbitrary equilateral parallelogram.
The following formulas apply to the 
lozenge. Its area for side
length 
is
 |
(1)
|
its diagonals have lengths
 |  |  |
(2)
|
 |  |  |
(3)
|
and it has inradius
 |
(4)
|
For an arbitrary rhombus of side length 
, the area is
 |
(5)
|
where 
and 
are its diagonal lengths and
is an interior
angle.
