Answer:
The area increases by 25.68
Explanation:
The surface area of a cuboid is 2lw + 2wh + 2lh, where l = length, w = width, and h = height. The current surface area is 2*18*3.4 + 2*3.4*30 + 2*18*30, which is 1406.4. If the height is increased by 0.6 cm, the surface area will be 2*18*3.4+2*3.4*30.6+2*18*30.6, which is 1432.08. The difference is surface area is 25.68