# Rhombus

• rhombus
two rhombi
edges and vertices4
schläfli symbol{ } + { }
coxeter diagram
symmetry groupdihedral (d2), [2], (*22), order 4
area (half the product of the diagonals)
dual polygonrectangle
propertiesconvex, isotoxal
the rhombus has a square as a special case, and is a special case of a kite and parallelogram.

in plane euclidean geometry, a rhombus (plural rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. the rhombus is often called a diamond, after the diamonds suit in playing cards which resembles the projection of an octahedral diamond, or a lozenge, though the former sometimes refers specifically to a rhombus with a 60° angle (see polyiamond), and the latter sometimes refers specifically to a rhombus with a 45° angle.

every rhombus is simple (non-self-intersecting), and is a special case of a parallelogram and a kite. a rhombus with right angles is a square.[1][2]

• etymology
• characterizations
• basic properties
• diagonals