Library/Geometry/Plane geometry/Quadrilaterals/General quadrilaterals

General quadrilaterals

Overview
Important

A general quadrilateral is a simple (non-self-intersecting) polygon with exactly four sides and four vertices. The sides can be of any length and the angles can be of any measure, as long as the shape is closed.

Important properties

  • The sum of the interior angles of any quadrilateral is 360 degrees.

  • General quadrilaterals do not have to have parallel sides or equal angles.

  • Diagonals of a general quadrilateral may or may not be equal or perpendicular.

  • Special types of quadrilaterals (like parallelograms, rectangles, squares, rhombuses, and trapeziums) have extra properties, but a general quadrilateral does not.