The shapes of elementary geometry are invariably convex. The point of intersection of the sides is not considered a vertex of the quadrilateral. A quadrilateral that is not simple is also known as self-intersecting to indicate that a pair of his non-adjacent sides intersect. So that two non-adjacent sides do not cross. In either case, the quadrilateral is simple, which means that the four sides of the quadrilateral only meet at the vertices, two at a time. The seldom used term quadrangle has exactly the same meaning as quadrilateral, however the two related terms - complete quadrangle and complete quadrilateral - describe essentially different configurations.Ī quadrilateral may be convex or concave (see the diagram below.) A quadrilateral that is concave has an angle exceeding 180 o.

Although we use words like pentagon and polygon, the term quadrilateral has completely replaced tetragon.

The Latin term is a partial translation of Greek tetragon, literally 'four angles,' since a closed figure with four angles also has four sides. Quadrilateral (noun, adjective): the first element is from Latin quadri- 'four' from the Indo-European root k wetwer- 'four.' The second element is from Latin latus, stem later-, 'side,' of unknown prior origin. Quadrilateral is a geometric shape that consists of four points ( vertices) sequentially joined by straight line segments ( sides).

Kite quadrilateral