|
|
|
|
|
|
Square centimetre (International spelling as used by the International Bureau of Weights and Measures) or square centimeter (American spelling), symbol cm2, is the SI unit of area or surface area.
The acre is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain by 1 furlong (66 by 660 feet), which is exactly equal to 1⁄640 of a square mile, 43,560 square feet, approximately 4,047 m2, or about 40% of a hectare.