You will study in detail the diagonals of quadrilaterals in middle and high school. However, they do hold special properties. The diagonals of parallelograms bisect each other. In the special cases of parallelograms, such as rectangles, the diagonals are equal in length, in rhombuses, the diagonals are perpendicular, and in squares, the diagonals are perpendicular bisectors. Kites also have perpendicular diagonals.