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 area of a lozenge of side length 
is
 |
(1)
|
its diagonals have lengths
 |  |  |
(2)
|
 |  |  |
(3)
|
and it has inradius
 |
(4)
|
