A rectangle is a four-sided plane figure with four right angles (90-degree angles) formed by two pairs of parallel sides of unequal length. The opposite sides of a rectangle are equal in length, and the length of its diagonals are also equal. A rectangle can be seen as a special type of parallelogram where the angles are all right angles. The area of a rectangle is calculated by multiplying the length and width of the rectangle, and its perimeter is calculated by adding the length of all four sides. Rectangles are used in many different applications such as in mathematics, engineering, architecture, and design. They are often used to represent objects such as windows, doors, and frames.
Rectangle appears frequently in nature and is used by many living organisms. For example, the shape of a typical fish body is a rectangle, and the shape of most plant leaves is also rectangular. This is because the rectangular shape allows for the efficient use of space, and it is often the most optimal shape for certain biological functions.
The rectangle is also a commonly used shape in design and architecture because of its versatility and simplicity. For example, in art, the golden rectangle, a rectangle with a length-to-width ratio of approximately 1.618, is often used as a visually pleasing and harmonious proportion in compositions. Additionally, many buildings, such as homes and offices, are designed using rectangular shapes for practicality and efficiency.