Rectangle
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2008-07-01T10:19:46Z
BOTarate
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robot Adding: [[be:Прамавугольнік]]
[[Image:shaperec.svg|right|200px|A rectangle]]
[[Image:Rectangle4x5.png|thumb|right|A 5 by 4 rectangle]]
In [[geometry]], a '''rectangle''' is defined as a [[quadrilateral]] where all four of its angles are [[right angle]]s. 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 (geometry)|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 [[multiplication|product]] of its length and its width; in symbols, <math>A=lw</math>. For example, the area of a rectangle with a length of 5 and a width of 4 would be 20, because <math>5 \times 4 = 20</math>.
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 (mathematics)|limit]] of [[addition|sum]]s of the areas of arbitrarily thin rectangles.
== See also ==
* Rectorsal
*[[Cuboid]]
*[[Hyperrectangle]]
*[[Rectangular function]]
*[[Square (geometry)]]
== External links ==
{{CommonsCat|Rectangles}}
* [http://www.elsy.at/kurse/index.php?kurs=Rectangle+and+Square&status=public Animated course (Construction, Circumference, Area)]
* {{MathWorld | urlname=Rectangle | title=Rectangle}}
*[http://www.mathopenref.com/rectangle.html Definition and properties of a rectangle] With interactive animation
*[http://www.mathopenref.com/rectanglearea.html Area of a rectangle] with interactive animation
[[Category:Quadrilaterals]]
[[ast:Rectángulu]]
[[ay:Wiskhalla]]
[[bn:আয়তক্ষেত্র]]
[[be:Прамавугольнік]]
[[be-x-old:Прастакутнік]]
[[bs:Pravougaonik]]
[[br:Skouergorneg]]
[[bg:Правоъгълник]]
[[ca:Rectangle]]
[[cs:Obdélník]]
[[da:Rektangel]]
[[de:Rechteck]]
[[et:Ristkülik]]
[[el:Ορθογώνιο παραλληλόγραμμο]]
[[es:Rectángulo]]
[[eo:Ortangulo]]
[[eu:Laukizuzen]]
[[fa:مستطیل]]
[[fr:Rectangle]]
[[ko:직사각형]]
[[hi:आयत]]
[[id:Persegi panjang]]
[[is:Rétthyrningur]]
[[it:Rettangolo]]
[[he:מלבן]]
[[ka:მართკუთხედი]]
[[sw:Mstatili]]
[[ht:Rektang]]
[[lo:ຮູບສີ່ແຈສາກ]]
[[la:Rectangulum]]
[[lv:Taisnstūris]]
[[lt:Stačiakampis]]
[[li:Rechhook]]
[[hu:Téglalap]]
[[nl:Rechthoek]]
[[ja:長方形]]
[[no:Rektangel]]
[[nn:Rektangel]]
[[km:ចតុកោណកែង]]
[[pl:Prostokąt]]
[[pt:Rectângulo]]
[[ro:Dreptunghi]]
[[qu:Wask'a]]
[[ru:Прямоугольник]]
[[scn:Rittànculu]]
[[simple:Rectangle]]
[[sk:Obdĺžnik]]
[[sl:Pravokotnik]]
[[szl:Prostokůnt]]
[[sr:Правоугаоник]]
[[fi:Suorakulmio]]
[[sv:Rektangel]]
[[tl:Parihaba]]
[[ta:செவ்வகம்]]
[[th:รูปสี่เหลี่ยมผืนผ้า]]
[[vi:Hình chữ nhật]]
[[tr:Dikdörtgen]]
[[uk:Прямокутник]]
[[vls:Rechtoek]]
[[zh:矩形]]