Square (geometry).

Square (geometry). Square (geometry), two-dimensional figure with four straight sides, whose four interior angles are right angles (90°), and whose four sides are of equal length. If the sides of a square have length s, the perimeter of the square is simply four times the length of a side, represented algebraically by the formula P = 4s. The area of a square is determined by multiplying the length of a side by itself: A = s2. A square is a special case of several broader types of four-sided figures: quadrilaterals, parallelograms, rhombuses, and rectangles. All squares are rectangles, for example, but not all rectangles are squares because many rectangles have pairs of sides that are not the same length. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.