# Surface

The surface or the surface is the dimension of a Surface. By Métonymie, one often indicates this dimension by the term “surfaces” itself (for example, one speaks about the “surface of a square” whereas it would be necessary to speak about its surface).

The term surface (of bottom Latin aired plane space) is used in Mathématiques.

The term surface is used mainly for grounds (surface of a garden, of a field) and is expressed (in the international system of units) in square meters (m ²).

Metric measures:

• Are (1 has = 100 m ²)
• Hectare (1 ha = 10.000 m ²)
• square kilometer (1 km = 1.000.000 m ² = 100 ha)

Other measurements:

## Calculation of the surface

The calculation of surface is a broad active field of mathematics of the Aire of usual surfaces until the integral calculus.

The calculation of the surface for elementary geometrical figures is simple. The more complex Polygone S can cut out in Triangle S, and one can then calculate the surface of each triangle:

in Euclidean Geometry, the surface of a triangle is half of the product length of its base by its height.

When it is about a surface delimited by a curve, one makes an approximation of this curve by a polygon and one applies the method above to have an approximation of the surface; if this curve can be expressed by a function, it is enough to calculate the Intégrale this function.

When it is about a Surface of revolution, it is enough to know the length of the arc of the Courbe planes generating this surface and the position of the Barycentre of the curve, then to apply the Théorème of Guldin.

One can compare surfaces by superposition, inclusion or decomposition-recombining. In this case measurement and calculation are useless. It is interesting to work on the surfaces in this way before learning the formulas from calculations for including/understanding the direction of the size concerned well.

## See too

• List of the countries by specific surface
• Surface

## External bond

Conversion of units of surface

Be-X-old: Плошча Simple: Area Zh-min-nan: Biān-chek Zh-yue: 面積

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