Area Calculator: Useful Online Tool And Application: The following are calculators to evaluate the area of seven common shapes. The area of more complex shapes can usually be obtained by breaking them down into their aggregate simple shapes and totalling their areas. This calculator is especially useful for estimating land area. The area is a quantity that describes the size or extent of a two-dimensional figure or shape in a plane. It can be visualized as the amount of paint that would be necessary to cover a surface and is the two-dimensional counterpart of the one-dimensional length of a curve, and three-dimensional volume of a solid. The standard unit of area in the International System of Units (SI) is the square meter or m2. Provided below are equations for some of the most common simple shapes, and examples of how the area of each is calculated. A rectangle is a quadrilateral with four right angles. It is one of the simplest shapes, and calculating its area only requires that its length and width are known (or can be measured). A quadrilateral by definition is a polygon that has four edges and vertices. In the case of a rectangle, the length typically refers to the longer two edges of the quadrilateral, while the width refers to the shorter of the two edges. When the length and width of a rectangle are equal, the shape is a special case of a rectangle, called a square. The equation for calculating the area of a rectangle is as follows: Imagine a farmer trying to sell a piece of land that happens to be perfectly rectangular. Because he owns some cows that he did not want frolicking freely, he fenced the piece of land and knows the exact length and width of each edge. The farmer also lives in the United States and being unfamiliar with the use of SI units, still measures his plot of land in terms of feet. The foot was defined to be exactly 0.3048 meters in 1959 after having changed over an extensive period of time, as historically, the human body was often used to provide a basis for units of length, and unsurprisingly, was inconsistent based on time and location. Tangent aside, the farmer's plot of land has a length of 220 feet, and a width of 99 feet.