# Dictionary Definition

rectangle n : a parallelogram with four right angles

# User Contributed Dictionary

## English

### Noun

rectangle (plural rectangles)
1. A quadrilateral having opposing sides parallel and four right angles.

#### Synonyms

• (quadrilateral): oblong (not in technical use)

# Extensive Definition

In geometry, a rectangle is defined as a quadrilateral where all four of its angles are right angles. A rectangle with vertices ABCD would be denoted as rectanglenotation ABCD.
From this definition, it follows that a rectangle has two pairs of parallel sides; that is, a rectangle is a parallelogram. A square is a special kind of rectangle where all four sides have equal length; that is, a square is both a rectangle and a rhombus. A rectangle that is not a square is colloquially known as an oblong.
Normally, of the two opposite pairs of sides in a rectangle, the length of the longer side is called the length of the rectangle, and the length of the shorter side is called the width.
The area of a rectangle is the product of its length and its width; in symbols, A=lw. For example, the area of a rectangle with a length of 5 and a width of 4 would be 20, because 5 \times 4 = 20.
In a rectangle the diagonals cross each other at their respective midpoints, under the same argument as for parallelograms. Unlike general parallelograms the two diagonals of a rectangle have the same length, the length of the diagonal can be found using the Pythagorean theorem.
In calculus, the Riemann integral can be thought of as a limit of sums of the areas of arbitrarily thin rectangles.

rectangle in Asturian: Rectángulu
rectangle in Aymara: Wiskhalla
rectangle in Bengali: আয়তক্ষেত্র
rectangle in Bosnian: Pravougaonik
rectangle in Breton: Skouergorneg
rectangle in Bulgarian: Правоъгълник
rectangle in Catalan: Rectangle
rectangle in Czech: Obdélník
rectangle in Danish: Rektangel
rectangle in German: Rechteck
rectangle in Estonian: Ristkülik
rectangle in Modern Greek (1453-): Ορθογώνιο παραλληλόγραμμο
rectangle in Spanish: Rectángulo
rectangle in Esperanto: Ortangulo
rectangle in Basque: Laukizuzen
rectangle in Persian: مستطیل
rectangle in French: Rectangle
rectangle in Korean: 직사각형
rectangle in Hindi: आयत
rectangle in Indonesian: Persegi panjang
rectangle in Icelandic: Rétthyrningur
rectangle in Italian: Rettangolo
rectangle in Hebrew: מלבן
rectangle in Georgian: მართკუთხედი
rectangle in Swahili (macrolanguage): Mstatili
rectangle in Haitian: Rektang
rectangle in Lao: ຮູບສີ່ແຈສາກ
rectangle in Latvian: Taisnstūris
rectangle in Lithuanian: Stačiakampis
rectangle in Limburgan: Rechhook
rectangle in Hungarian: Téglalap
rectangle in Dutch: Rechthoek
rectangle in Japanese: 長方形
rectangle in Norwegian: Rektangel
rectangle in Norwegian Nynorsk: Rektangel
rectangle in Central Khmer: ចតុកោណកែង
rectangle in Polish: Prostokąt
rectangle in Portuguese: Rectângulo
rectangle in Romanian: Dreptunghi
rectangle in Russian: Прямоугольник
rectangle in Sicilian: Rittànculu
rectangle in Simple English: Rectangle
rectangle in Slovak: Obdĺžnik
rectangle in Slovenian: Pravokotnik
rectangle in Serbian: Правоугаоник
rectangle in Finnish: Suorakulmio
rectangle in Swedish: Rektangel
rectangle in Tagalog: Parihaba
rectangle in Tamil: செவ்வகம்
rectangle in Thai: รูปสี่เหลี่ยมผืนผ้า
rectangle in Vietnamese: Hình chữ nhật
rectangle in Turkish: Dikdörtgen
rectangle in Ukrainian: Прямокутник
rectangle in Vlaams: Rechtoek
rectangle in Chinese: 矩形