A closed two-dimensional shape (polygon) bounded by four straight-line segments of equal length (equilateral) joined at four equal (right) angles. The formula with which to find its area: the length of one side squared (see below). The distance between opposite corners is the square root (see below) of the sum of the square of two sides. A quantity is squared when it is multiplied once by the same quantity (for example, 4 squared=4x4=16). The square root is the divisor of a quantity that when squared gives the quantity (for example, the square root of 4 is 2, because 4/2=2, and 2x2=4).Also see angle, dado, frame, mathematics, oblong, parallelogram, polygon, quadrilateral, rectangle, rhombus, right angle, trapezium, and trapezoid.