Contact us A quadrilateral is a shape of plane geometry with four straight sides and four vertices (corners). The side lengths and the angles of the vertices are not necessarily equal; neither do they need to have any specific values.

The sum of the four angle measures of a square is always 3600.

## Categories

Quadrilaterals can be divided into the following categories:

 Type and description Formulas Square All four sides of a square areof equal length and all fourangle are 90° (right angles). Area Circumference Diagonal length Area of the inscribed circle Area of the circumscribed circle Rhombus All four side of a Rhombus areof equal length. The angles arepairwise equal but notnecessarily 90°. Area   Circumference Rectangle The sides of a rectangle arepairwise of equal length,and allfour angles are 90° (right angles). Area Circumference Diagonal length Parallelogram The sides of a parallelogramare pairwise of equal length andparallel. The angles are pairwiseequal but not necessarily 90°. Area  Circumference Trapezoid Two sides of a trapezoid areparallel. Height or where and Area Circumference  Diagonal length    Trapezium A trapezium has not necessarilyparallel sides or right angles. The area can be determinedby dividing the trapeziuminto two triangles and then calculate the area of each of them with the formula: The circumference is thesum of all side lengths.

## Quadrilaterals fitting into more than one category.

The different categories of quadrilaterals do not exclude each other.

A square is also a rectangle, for instance. In everyday language, however, the word rectangle is normally referred to as a quadrilateral having four right angles but only sides with pairwise equal length.

 The quadrilateral is a but it is also a Square rectangle, Rhombus, Parallelogram, Trapezoid, Trapezium Rhombus Parallelogram, Trapezoid, Trapezium rectangle Parallelogram, Trapezoid, Trapezium Parallelogram Trapezoid, Trapezium Trapezoid Trapezium         