Answer:
644 cm³
Explanation:
Surface area of the composite figure = (surface area of the upper cuboid - base area of upper cuboid) + (surface area of the lower cuboid - base area of the upper cuboid)
✔️Surface area of upper cuboid = 2(LW + LH + WH)
L = 3
W = 3
H = 8
Surface area of upper cuboid = 2(3*3 + 3*8 + 3*8) = 2(9 + 24 + 24) = 114 cm²
✔️Surface area of Surface area of lower cuboid = 2(LW + LH + WH)
L = 12
W = 10
H = 7
Surface area of lower cuboid = 2(12*10 + 12*7 + 10*7) = 2(120 + 84 + 70) = 548 cm²
✔️Base area of upper cuboid = L*W
L = 3
W = 3
Base area = 3*3 = 9 cm²
✅Surface area of the composite figure = (114 - 9) + (548 - 9) = 105 + 539 = 644 cm³