Here is a handy little tool you can use to convert units of area beetween various measurement systems like: hectare to acre, acre to hectare, hectares to meters, hectares to m2, Square Kilometers to Hectares,Square Centimeters to Squere Inches, Square Miles to Km2, Square Yards to Square Feet, Square Inches to cm2, and so on. You can you can find responses to questions like: 'how many square feet make one square meter', 'how many acres are in a hectare', 'how many meters are in a hectare', 'how many feet are in an acre', etc.
Note: the acre is the only unit of area in common use, other than the square-foot, and the square mile. The rood is an area of 1 furlong by 1 rod, or 1210 sq. yds. An acre is four roods.