**Area** is a quantity expressing the two-dimensional size of a defined part of a surface, typically a region bounded by a closed curve. The term surface area refers to the total area of the exposed surface of a 3-dimensional solid, such as the sum of the areas of the exposed sides of a polyhedron. Area is an important invariant in the differential geometry of surfaces. To find the area of the rectangle with sides l and w ; **A= l * w ** where A is Area and l is lenght and w is a width. To find the area of perfect square; **A= a*a or aČ **where a is the length of the side of the square. To find the area of a circle; **A=pi*rČ** where pi=3.1416 and r is the radius of a circle.