Area

Encyclopedia : A : AR : ARE : Area

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

Contents

1 Units
2 Useful formulas
3 See also
4 External links

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#redirect [[Template:Fact]]) = 3.34450944 square metres

cadastral moon(acre) = 1600? square fathoms = 5755 square metres ^{[[Citing sources citation needed]]}

Useful formulas

Common equations for area:
Shape Equation Variables
A rectangle [l \cdot w \,] [l] and [w] are the lengths of the rectangles sides (length and width).
A triangle [\fracb \cdot h \,] [b] and [h] are the base and altitude (height), respectively.
A disk [\pi \cdot r^2 \,] r is the radius.
An ellipse [\pi \cdot a \cdot b \,] [a] and [b] are the semi-major and semi-minor axis.
A sphere [4 \pi r^2 \,], or [\pi d^2 \,] [r] is the radius and [d] the diameter.
A trapezoid [\frac(a+b)h \,] [a] and [b] are the parallel sides and [h] the distance (height) between the parallels.
A cylinder [2 \pi r (h + r) \,] [r] and [h] are the radius and height, respectively.
The lateral surface area of a cylinder [2 \pi r h \,] [r] and [h] are the radius and height, respectively.
A cone [\pi r (l + r) \,] [r] and [l] are the radius and slant height, respectively.
The lateral surface area of a cone [\pi r l \,] [r] and [l] are the radius and slant height, respectively.
A circular sector [\frac r^2 \theta \,] [r] and [\theta] are the radius angle (in radians), respectively.

Common equations for area:
Shape	Equation	Variables
A rectangle	[l \cdot w \,]	[l] and [w] are the lengths of the rectangles sides (length and width).
A triangle	[\fracb \cdot h \,]	[b] and [h] are the base and altitude (height), respectively.
A disk	[\pi \cdot r^2 \,]	r is the radius.
An ellipse	[\pi \cdot a \cdot b \,]	[a] and [b] are the semi-major and semi-minor axis.
A sphere	[4 \pi r^2 \,], or [\pi d^2 \,]	[r] is the radius and [d] the diameter.
A trapezoid	[\frac(a+b)h \,]	[a] and [b] are the parallel sides and [h] the distance (height) between the parallels.
A cylinder	[2 \pi r (h + r) \,]	[r] and [h] are the radius and height, respectively.
The lateral surface area of a cylinder	[2 \pi r h \,]	[r] and [h] are the radius and height, respectively.
A cone	[\pi r (l + r) \,]	[r] and [l] are the radius and slant height, respectively.
The lateral surface area of a cone	[\pi r l \,]	[r] and [l] are the radius and slant height, respectively.
A circular sector	[\frac r^2 \theta \,]	[r] and [\theta] are the radius angle (in radians), respectively.

External links

[Area Conversion]

[[zh-min-nan:Bīn-chek]]

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