Rhombus
A quadrilateral with both pairs of opposite sides parallel and all sides the same length, i.e., an equilateral parallelogram.
The word rhomb is sometimes used instead of rhombus, and a rhombus is sometimes also
called a diamond. A rhombus with 
is sometimes called a lozenge.
The polygon diagonals 
and 
of a rhombus are
perpendicular and satisfy
 |
(1)
|
The diagonals are related to the opening angle 
by
 |  |  |
(2)
|
 |  |  |
(3)
|
The area of a rhombus is given by
 |  |  |
(4)
|
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(5)
|
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(6)
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The rhombus is a tangential quadrilateral with 
, and so has inradius
 |  |  |
(7)
|
 |  |  |
(8)
|
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rhombus
