A parallelogramMathworldPlanetmath is a quadrilateralMathworldPlanetmath whose opposite sides are parallelMathworldPlanetmathPlanetmathPlanetmath.

Some special parallelograms have their own names: squares, rectanglesMathworldPlanetmath, rhombuses. A rectangle is a parallelogram whose all angles are equal (i.e. 90), a rhombus is a parallelogram whose all sides are equal, and a square is a parallelogram that is a rectangle and a rhombus at the same time.

Every parallelogram have their opposite sides and opposite angles equal. Also, adjacentPlanetmathPlanetmathPlanetmath angles of a parallelogram always add up to 180, and the diagonalsMathworldPlanetmath bisect each other.

A base of a parallelogram is one of its sides. Any side of a parallelogram can be selected as its base. Once a base has been selected, the height of the parallelogram is defined to be the length of any line segmentMathworldPlanetmath perpendicularMathworldPlanetmathPlanetmath to the base which extends from the base to the opposite side parallel to the base. The area of a parallelogram with base length b and height h is given by the formula  A=bh.

There is also a neat relation between the length of the sides and the lengths of the diagonals called the parallelogram lawMathworldPlanetmath.

Title parallelogram
Canonical name Parallelogram
Date of creation 2013-03-22 12:02:21
Last modified on 2013-03-22 12:02:21
Owner drini (3)
Last modified by drini (3)
Numerical id 11
Author drini (3)
Entry type Definition
Classification msc 51-00
Related topic ParallelogramTheorems
Related topic Quadrilateral
Related topic Rectangle
Related topic Rhombus
Related topic Square
Related topic ParallelogramLaw
Related topic Kite
Related topic RhomboidMathworldPlanetmath
Related topic ProofOfParallelogramTheorems
Related topic ParallelotopeMathworldPlanetmath