Square (geometry)
A square is a quadrilateral in which all sides have equal length and all angles are right angles.
Equivalently, the squares are the regular quadrilaterals.
Introductory
Area
The area of a square can be found by squaring the square's side length: the area of a square with side length is .
Perimeter
The perimeter of a square can be found by multiplying the square's side length by four - .
Diagonal
The length of either diagonal of a square can be obtained by the Pythagorean theorem.