The rhombus is the parallelogram with two consecutive congruent sides.

Because the rhombus is a particular parallelogram, all the properties of the parallelogram are also valid for the rhombus.



  • all sides are congruent;
  • the diagonals are (reciprocally) perpendicular;
  • diagonals are also bisectors of angles;
  • the perimeter is four times the side;
  • the area is equal to half the product of the diagonals;
  • the area is four times larger than the area of ​​the right triangle formed by one side and the two half-diagonals.
  • the opposite sides are parallel and congruent;
  • opposite angles are congruent (equal), adjacent angles are supplementary;
  • the diagonals are cut into congruent segments (“halved”);
  • the area is equal to twice the area of ​​the triangle formed by two adjacent sides and the diagonal opposite them.