4.125: Calculate the surface area of a rectangular parallelepiped with dimensions a) 2 dm, 4 dm, and 6 dm; b) 6 m, 7 m, and 13 dm.

a) Surface area = 2 * (ab + ac + bc) = 2 * (2×4 + 2×6 + 4×6) = 2 * (8 + 12 + 24) = 88 dm²; b) Convert 13 dm to meters (13 dm = 1.3 m). Surface area = 2 * (ab + ac + bc) = 2 * (6×7 + 6×1.3 + 7×1.3) = 2 * (42 + 7.8 + 9.1) = 2 * 58.9 = 117.8 m².