What are the shapes that diagonals are congruent?

Diagonals are congruent in several geometric shapes, most notably in rectangles, rhombuses, and squares. In a rectangle, the diagonals are equal in length due to its right angles. In a rhombus, although the angles are not right angles, the diagonals bisect each other at right angles and are equal in length. In a square, which is a special case of both a rectangle and a rhombus, the diagonals are congruent as well.