In geometry , a rectangle is a shape with four sides and four corners. The corners are all right angles . It follows that the pairs of sides opposite each other must be parallel and of the same length.

People make many rectangular things, including most tables , boxes, books, and papers. The word comes from Latin words meaning "right" and angle".

A rectangle whose four sides have the same length is called a square .

Formulas [ change | change source ]

If a rectangle has length ${\displaystyle \ell }$ and width w , then :

• It has area ${\displaystyle K=\ell w}$.
• it has perimeter ${\displaystyle P=2\ell +2w=2(\ell +w)\,}$. ^[1]
• Each diagonal has length ${\displaystyle d={\sqrt {\ell ^{2}+w^{2}}}}$. ^{[2] [3]}
• it has an aspect ratio of ${\displaystyle \ell }$ : w.
• When ${\displaystyle \ell =w\,}$, the rectangle is a square .
• When ${\displaystyle \ell /w}$ is equal to the golden ratio , the rectangle is called a golden rectangle . ^[2]

Related pages [ change | change source ]

• Matrix (mathematics)
• Quadrilateral
• Rhombus

References [ change | change source ]

1. ↑ "List of Geometry and Trigonometry Symbols" . Math Vault . 2020-04-17 . Retrieved 2020-09-25 .
2. ↑ ^{2.0 2.1} "Rectangle" . www.mathsisfun.com . Retrieved 2020-09-25 .
3. ↑ Weisstein, Eric W. "Rectangle" . mathworld.wolfram.com . Retrieved 2020-09-25 .

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