Area

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This article explains the meaning of area as a physical quantity. The article area (geometry) is more mathematical. See also area (disambiguation).

Area is a physical quantity expressing the size of a part of a surface. The term can also be used in a non-mathematical context to be mean "vicinity".

Surface area is the summation of the areas of the exposed sides of an object.

Contents

[edit] Mathematical Usage

[edit] Units

Units for measuring surface area include:

square metre = SI derived unit
are = 100 square metres
hectare = 10,000 square metres
square kilometre = 1,000,000 square metres
square megametre = 1012 square metres

Imperial units, as currently defined from the metre:

square foot (plural square feet) = 0.09290304 square metres
square yard = 9 square feet = 0.83612736 square metres
square perch = 30.25 square yards = 25.2928526 square metres
acre = 160 square perches or 43,560 square feet = 4046.8564224 square metres
square mile = 640 acres = 2.5899881103 square kilometres

Old European area units, still in used in some private matters (e.g. land sale advertisements)

square fathom (fahomia in some sources[citation needed]) = 3.34450944 square metres
cadastral moon(acre) = 1600? square fathoms = 5755 square metres [citation needed]

[edit] Useful formula

Common equations for area:
Shape Equation Variables
Rectangle <math>l \cdot w \,</math> <math>l</math> and <math>w</math> are the lengths of the rectangles sides (length and width).
Triangle <math>\frac{1}{2}b \cdot h \,</math> <math>b</math> and <math>h</math> are the base and altitude (height), respectively.
Disk* or Circle <math>\pi \cdot r^2 \,</math> r is the radius.
Ellipse <math>\pi \cdot a \cdot b \,</math> <math>a</math> and <math>b</math> are the semi-major and semi-minor axis.
Sphere, Circular area <math>4 \pi r^2 \,</math>, or <math>\pi d^2 \,</math> <math>r</math> is the radius and <math>d</math> the diameter.
Trapezoid <math>\frac{1}{2}(a+b)h \,</math> <math>a</math> and <math>b</math> are the parallel sides and <math>h</math> the distance (height) between the parallels.
Cylinder <math>2 \pi r (h + r) \,</math> <math>r</math> and <math>h</math> are the radius and height, respectively.
Lateral surface area of a cylinder <math>2 \pi r h \,</math> <math>r</math> and <math>h</math> are the radius and height, respectively.
Cone <math>\pi r (l + r) \,</math> <math>r</math> and <math>l</math> are the radius and slant height, respectively.
Lateral surface area of a cone <math>\pi r l \,</math> <math>r</math> and <math>l</math> are the radius and slant height, respectively.
Circular sector <math>\frac{1}{2} r^2 \theta \,</math> <math>r</math> and <math>\theta</math> are the radius and angle (in radians), respectively.

* A disk is the area enclosed in a circle. Often such area is called cross-sectional area like a cable or wire.

[edit] See also


[edit] External links

als:Fläche ar:مساحة ast:Superficie zh-min-nan:Biān-chek be:Плошча bg:Площ ca:Àrea cs:Povrch cy:Arwynebedd da:Areal de:Fläche (Topologie) et:Pindala el:Έκταση es:Superficie eo:Areo eu:Azalera fa:مساحت fo:Vídd fr:Superficie gu:ક્ષેત્રફળ ko:면적 hr:Površina io:Areo ilo:Kalawa id:Luas ia:Superficie is:Flatarmál he:שטח (מתמטיקה) ka:ფართობი la:Area lv:Platība lt:Plotas li:Oppervlak mk:Плоштина mg:Velarantany ms:Keluasan nl:Oppervlakte no:Areal nn:Flatevidd oc:Superficia pl:Powierzchnia pt:Área ro:Suprafaţă ru:Площадь simple:Area fi:Pinta-ala sv:Ytmått ta:பரப்பளவு th:พื้นที่ vi:Diện tích uk:Площа zh:面积

Area

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