arealet

Arealet is the Norwegian term for the area, the two-dimensional measure of the extent of a surface or region. In mathematics, area assigns a nonnegative size to a planar region and is used across the sciences and in everyday measurements. The concept extends to higher dimensions, with surface area describing the boundary of a solid.

Common shapes have standard formulas: rectangle area equals length times width; square area equals side squared; triangle area equals one-half base times height; circle area equals pi times radius squared. For irregular regions, area can be found by triangulation, decomposition into simple shapes, or by evaluating a double integral. In computational contexts, the shoelace formula provides area from polygon vertex coordinates.

Area is expressed in square meters (m²) in the metric system. For larger areas, hectares (ha, 10,000 m²) are used; historically, the unit are (100 m²) was used in land measurements. Arealet data are common in land use planning, GIS, forestry, ecology, and geography, where the areal extent of regions is a fundamental attribute.

Areal should be distinguished from surface area, which measures the outer boundary of a three-dimensional object, and from volume, which measures three-dimensional space. In practice, arealet is a foundational concept across geometry, geography, and related disciplines.