Let the rectangle have length L and width W.
The intersection of the diagonals is at the center of the rectangle. Therefore, its distance to the shorter side would be (L / 2), and the distance to the longer side would be (W / 2). We are given that (L / 2) = (W / 2) + 4. This simplifies to L = W + 8.
The perimeter of the rectangle, 2L + 2W = 56. Substituting L = W + 8:
2W + 16 + 2W = 56
W = 10
L = W + 8 = 18
The rectangle measures 10 cm by 18 cm.