Area
This article is about the physical quantity. For other uses, see 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.
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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
- 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
Useful formulae
Shape | Equation | Variables |
---|---|---|
Square | s is the length of the side of the square. | |
Regular hexagon | s is the length of one side of the hexagon. | |
Regular octagon | s is the length of one side of the octagon. | |
Perfect Hexagon | w is the width of one side when all sides are equal. | |
Perfect Octagon | w is the width of one side when all sides are equal. | |
Any regular polygon | a is the apothem, or the radius of an inscribed circle in the polygon, and p is the perimeter of the polygon. | |
Any regular polygon | P is the Perimeter and n is the number of sides. | |
Any regular polygon | P is the Perimeter and n is the number of sides. | |
Rectangle | l and w are the lengths of the rectangle's sides (length and width). | |
Parallelogram (in general) | b and h are the length of the base and the length of the perpendicular height, respectively. | |
Rhombus | a and b are the lengths of the two diagonals of the rhombus. | |
Triangle | b and h are the base and altitude (height), respectively. | |
Disk* or Circle | r is the radius. | |
Circle, Circular area | , or | r is the radius and d the diameter. |
Ellipse | a and b are the semi-major and semi-minor axes, respectively. | |
Trapezoid | a and b are the parallel sides and h the distance (height) between the parallels. | |
Total surface area of a Cylinder | r and h are the radius and height, respectively. | |
Lateral surface area of a cylinder | r and h are the radius and height, respectively. | |
Total surface area of a Cone | r and l are the radius and slant height, respectively. | |
Lateral surface area of a cone | r and l are the radius and slant height, respectively. | |
Total surface area of a Sphere | or | r and d are the radius and diameter, respectively. |
Total surface area of an ellipsoid | See the article. | |
Circular sector | r and θ are the radius and angle (in radians), respectively. | |
Square to circular area conversion | A is the area of the square in square units. | |
Circular to square area conversion | C is the area of the circle in circular units. |
* A disk is the area enclosed in a circle. Often such area is called cross-sectional or circular area like a round cable cut in half!
See also
- Volume
- Orders of magnitude (area) — A list of areas by size.
- Equi-areal mapping
External links
Look up Area in
Wiktionary, the free dictionary.
Wiktionary, the free dictionary.