AREA | Class 8 Mathematics Notes

Properties of Rectangle

A rectangle is a quadrilateral with four right angles (each 90°). The opposite sides of a rectangle are equal and parallel. This means that if one side is of length 'l' and the adjacent side is 'b', then the opposite sides will also be 'l' and 'b' respectively. The diagonals of a rectangle are equal in length and bisect each other. This property is useful in proving congruence and similarity in geometry. The sum of the interior angles of a rectangle is 360°, as with any quadrilateral. Rectangles are widely used in construction and design due to their regular shape and symmetry. Understanding these properties helps in calculating area, perimeter, and other measurements accurately. The rectangle is a special type of parallelogram where all angles are right angles. This section also explains how to identify rectangles in different orientations and how their properties remain consistent regardless of rotation or reflection.

📊 Diagram: The diagram shows a rectangle ABCD with sides AB and CD equal, sides BC and AD equal, and all angles marked as 90°. The diagonals AC and BD are drawn and shown to be equal in length and intersecting at point O, which bisects both diagonals.

🧪 Activity: Activity: Using a rectangular sheet of paper, students fold it along the diagonal to observe that the two triangles formed are congruent, demonstrating that diagonals bisect each other and are equal.

🔗 Connection: This section sets the foundation for the next section on properties of squares, which are a special type of rectangle.