Properties of the diagonals of a rectangle: Property 1 — Equal length. In rectangle ABCD, triangle ABD and triangle ABC are congruent (same base AB, same height, right angles at corners). Therefore diagonal AC = diagonal BD. ✓ Property 2 — Bisect each other. The diagonals of any parallelogram (including a rectangle) bisect each other. So AO = OC and BO = OD, where O is the intersection point. ✓ Property 3 — NOT perpendicular (unless it is also a square). In a general rectangle, the diagonals cross at an angle that is NOT 90°. Perpendicular diagonals are a property of squares and rhombuses only. ✗ Property 4 — NOT lines of symmetry. A rectangle has exactly 2 lines of symmetry: the vertical and horizontal midlines. The diagonals are not lines of symmetry for a non-square rectangle. ✗ Correct statement: The diagonals AC and BD are equal in length.