In geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, or (100-gradian angles or right angles). It can also be defined as a rectangle in which two adjacent sides have equallength. A square with vertices ABCD would be denoted
◻
{\displaystyle \square }
ABCD.
Characterizations
A convex quadrilateral is a square if and only if it is any one of the following:
A square is a special case of a rhombus (equal sides, opposite equal angles), a kite (two pairs of adjacent equal sides), a trapezoid (one pair of opposite sides parallel), a parallelogram (all opposite sides parallel), a quadrilateral or tetragon ( four -sided polygon), and a rectangle (opposite sides equal, right -angles) and therefore has all the properties of all these shapes, namely:
The diagonals of a square bisect each other and meet at 90°