Area - Definition and Overview

This article explains the meaning of area as a Physical quantity. Article area (geometry) is more mathematical.

Area is a quantity expressing the size of a region of space. Surface area refers to 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

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

Cross sectional area of electrical wire

Rough figures for the cross sectional area of copper conductor:

CSA (mm²)     diameter (mm)          current (A)
 1.0             2.8                  13
 1.5             3.5                  17
 2.5             4.2                  24
 4.0             4.8                  32
 6.0             5.4                  41
10.0             6.8                  55
16.0             8.0                  74
25.0             9.8                  97