"In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. It can also be defined as an equiangular quadrilateral, since equiangular means that all of its angles are equal (360\u00B0/4 = 90\u00B0). It can also be defined as a parallelogram containing a right angle. A rectangle with four sides of equal length is a square."@en . . .