Rectangle 70048 222835473 2008-07-01T10:19:46Z BOTarate 5870361 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]]