it is important to realise that an acre can be measured in any shape from rectangles to circles or even hexagons so long as the total area of land is 43560 square feet the most common shape for an acre is 1 furlong by 1 chain or 660 feet by 66 feett is important to realise that an acre can be measured in any shape from rectangles to circles or even hexagons so long as the total area of land is 43560 square feet the most common shape for an acre is 1 furlong by 1 chain or 660 feet by 66 feet