A rectangle is a four-sided polygon, known as a quadrilateral, characterized by having opposite sides that are equal in length and four right angles (90 degrees). The formula for calculating the area of a rectangle is length multiplied by width, while the perimeter can be found by adding the lengths of all four sides. Rectangles are commonly found in everyday life, such as in the shape of books, screens, and tables. They are also used in various fields, including architecture and design, due to their straightforward geometry and efficient use of space.