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.

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 fathomor fahomia in some sources = 3.5967 square metres

cadastral moon(acre) = 1600� square fathoms = 5755 square metres

The article Orders of magnitude links to lists of objects of comparable surface area.

Useful formulas

Area of a rectangle (and, in particular, a square): length × width
Area of a triangle: ½ × base × height
Area of a disk: π × r²
Area of an ellipse: π × a × b
Area of a sphere: 4 × π × r² = π × d² (which is the first derivative of the formula for volume of a sphere)
Area of a trapezoid: If a and b are the two parallel sides and h is the distance (height) between the parallels, the area formula is as below:

$A=\frac{1}{2}(a+b)h$ or $A=\frac{h(a+b)}{2}$

Total surface area of a right circular cylinder: 2 × π × r × (h + r)
Lateral surface area of a right circular cylinder: 2 × π × r × h
Total surface area of a right circular cone: π × r × (l + r)
Lateral surface area of a right circular cone: π × r × l
Area of a surface of revolution:

$S_{area}=2 \pi \int_{a}^{b} f(x) \sqrt{1+(f'(x))^2}dx$

External links

Area Converter
Area Conversion table

The content of this page is retrieved from http://en.wikipedia.org/wiki/Area under GFDL