Question

A cuboid is 12 cm long, 9 cm broad and 8 cm high. Its total surface area is
(a) 864 cm²
(b) 552 cm²
(c) 432 cm²
(d) 276 cm²

Answer 1

(b) 552 cm²

$$\begin{gathered} \mathrm{Total}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cuboid}=2\left(lb+bh+lh\right){\mathrm{cm}}^2 \\ =2(12\times 9+8\times 9+12\times 8){\mathrm{cm}}^2 \\ =2\left(108+72+96\right){\mathrm{cm}}^2 \\ =552{\mathrm{cm}}^2 \end{gathered}$$