The area of a region is the amount of space which it occupies.
Area is normally measured using squares. For small regions
standard units of area are square centimeters and square millimeters.
Large regions are measured in square metres (m2)
or square kilometers (km2). Fields are usually
measured in hectares. Where 1 hectare equals 10000 m2,
although the traditional unit was the acre equal to 4840 square
yards, which is about half the area of a soccer pitch.
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.