A square foot is by definition the area enclosed by a square with sides each 1 foot long. One square foot is equal to 0.09290304 square metres for the international, English foot. This article explains the meaning of area as a physical quantity. ... In plane geometry, a square is a polygon with four equal sides and equal angles. ... A foot (plural: feet) is a non-SI unit of distance or length, measuring around a third of a metre. ... A square metre (US spelling: square meter) is by definition the area enclosed by a square with sides each 1 metre long. ...