A quadrilateral is a polygon that has four sides. The following are a few examples.

Parts of quadrilateral

Quadrilateral ABCD, shown below, has the following properties:

Special quadrilaterals

Quadrilaterals are widely studied in geometry. They are often categorized further based on their angles and sides.


A parallelogram is a quadrilateral with two pairs of parallel sides. The opposite angles and sides of a parallelogram are congruent.


A rectangle is a quadrilateral with four right angles. The opposite sides of a rectangle are congruent and parallel.


A rhombus is a quadrilateral with four congruent sides. The opposite sides of a rhombus are parallel. The opposite angles of a rhombus are congruent.


A square is quadrilateral with four congruent sides and four congruent angles. The four angles of a square are right angles. A square is a regular quadrilateral.


A trapezoid is a quadrilateral with one pair of parallel opposite sides.


A kite is a quadrilateral with two pairs of congruent adjacent sides.

The following diagram summarizes the various quadrilaterals described above.