Square (geometry)

A square is quadrilateral in which all sides have equal length and all angles are right angles.

Equivalently, the squares are the regular quadrilaterals.

Introductory

The area of a square can be found by squaring the square's side length: the area $A$ of a square with side length $s$ is $A = s^2$ .

The perimeter $P$ of a square can be found by multiplying the square's side length by four - $P = 4s$ .

The length of either diagonal of a square can be obtained by the Pythagorean theorem. $D=\sqrt{s^2+s^2}=s\sqrt{2}$