Plane figure · Quadrilaterals
Square
Four equal sides and four right angles.
Dimensions
Results
area A
perimeter P
diagonal d
Formulas
The square is a rectangle with both sides equal. Its diagonal is the hypotenuse of a right triangle with two legs a, so by Pythagoras d² = a² + a².
Checked: the A formula agrees with a Monte Carlo measurement of the shape itself, made from its geometric definition, every time the site is built.
Topology lens
Topologically a disc, like every figure here without a hole: Euler characteristic 1. Stretching turns it into a circle, a square or a star. More on the lens.