Category
page 1Quadrilaterals
quadrilateral
In geometry, a quadrilateral is a four-sided polygon, having four edges (sides) and four corners (vertices). The word is derived from the Latin words quadri, a variant of four, and latus, meaning "side". It is also called a tetragon, derived from Greek "tetra" meaning "four" and "gon" meaning "corner" or "angle", in analogy to other polygons (e.g. pentagon). Since "gon" means "angle", it is analogously called a quadrangle, or 4-angle. A quadrilateral with vertices A, B, C and D is sometimes denoted as \square ABCD.
square number
product of some integer with itself
Newton line
centered square number
subclass of centered polygonal number
Happy Ending problem
problem about proving that five points in the plane will have a subset forming the vertices of a convex quadrilateral
orthocentric system
polite number
positive integer that can be written as the sum of two or more consecutive positive integers