Area, in plane geometry, is the amount of surface contained within the boundaries of a plane figure. It is generally expressed in square units. For example, a square inch is a square whose sides are each 1 inch in length. Other units of area include square feet, square miles, and square meters. The area of most common plane figures can be calculated from certain of their dimensions. Thus, a rectangle’s area can be found by multiplying the lengths of two adjoining sides. The word area can also mean the measure of a curved surface or the measure of the surface of a solid figure, in which case it is called surface area. See also Calculus (Finding areas) ; Metric system (Use of related units) (Non-SI metric units) ; Square measure ; Weights and measures .
