Complete Quadrangle

In mathematics, specifically projective geometry, a complete quadrangle is a system of geometric objects consisting of any four points in a plane, no three of which are on a common line, and of the six lines connecting each pair of points. Dually, a complete quadrilateral is a system of four lines, no three of which pass through the same point, and the six points of intersection of these lines. The complete quadrangle was called a tetrastigm by Lachlan (1893), and the complete quadrilateral was called a tetragram; those terms are occasionally still used.

Read more about Complete Quadrangle:  Diagonals, Projective Properties, Euclidean Properties

Famous quotes containing the word complete:

    We have lost the art of living; and in the most important science of all, the science of daily life, the science of behaviour, we are complete ignoramuses. We have psychology instead.
    —D.H. (David Herbert)