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)