# Formulas and Tables

Elementary Geometry# Rectangle

Diagonal of a rectangle: \(d\)

Radius of the circumscribed circle: \(R\)

Perimeter of a rectangle: \(P\)

Area of a rectangle: \(S\)

- A rectangle is a quadrilateral in which all four angles are right angles (equal to \(90^\circ\)).

- Diagonal of a rectangle

\(d = \sqrt {{a^2} + {b^2}} \) - Radius of the circumscribed circle

\(R = d/2\) - Perimeter of a rectangle

\(P = 2\left( {a + b} \right)\) - Area of a rectangle

\(S = ab\)