A complete reference guide to quadrilaterals including squares, rectangles, parallelograms, trapezoids, and rhombus. It provides definitions and interactive activities that enhance further explanation.

MathWorld provides multiple definitions and formulas for the mathematical term, square.

Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.