Area

Area is a quantity expressing the two-dimensional size of a defined part of a surface, typically a region bounded by a closed curve. The term surface area refers to the total area of the exposed surface of a 3-dimensional solid, such as the sum of the areas of the exposed sides of a polyhedron.

Units
Units for measuring surface area include:
 * Metric
 * square metre (m²) = SI derived unit
 * are (a) = 100 square metres (m²)
 * hectare (ha) = 10,000 square metres (m²)
 * square kilometre (km²) = 1,000,000 square metres (m²)
 * square megametre (Mm²) = 1012 square metres
 * square foot = 144 square inches = 0.09290304 square metres (m²)
 * square yard = 9 square feet = 0.83612736 square metres (m²)
 * square perch = 30.25 square yards = 25.2928526 square metres (m²)
 * acre = 160 square perches or 4,840 square yards or 43,560 square feet = 4046.8564224 square metres (m²)
 * square mile = 640 acres = 2.5899881103 square kilometres (km²)

Useful formulas


All of the above calculations show how to find the area of many shapes.