Area of a Rectangle Calculator

A rectangle is a two-dimensional four-sided polygon, or quadrilateral, characterized by having four interior right angles measuring 90 degrees each. Its opposite sides are strictly parallel and equal in length. While a square is technically a special type of rectangle where all four sides are equal, standard rectangles feature two longer sides called lengths and two shorter sides called widths.

To find the area of a rectangle, multiply its length by its width, which gives you the total two-dimensional space inside the boundaries measured in square units. To find the perimeter, add the length and width together and multiply that sum by two, which gives you the total linear distance around the outside edge of the shape.

To find the area when dimensions use mixed units, you must first convert them to a uniform measurement system. Convert 3 feet into inches by multiplying by 12, giving you 36 inches. Then, multiply 36 inches by the 4-inch width, resulting in an area of 144 square inches, which is equivalent to exactly 1 square foot.

To verify if a four-sided shape is a rectangle, check two main properties: all four interior corners must be precisely 90-degree right angles, and the opposite sides must be equal in length. Alternatively, you can measure both diagonals from corner to corner; if the two diagonal line segments are completely equal in length, the shape is guaranteed to be a rectangle.