A cuboid is 12 cm long, 9 cm broad and 8 cm high. Its total surface area is
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

Solution:

(b) $552 \mathrm{~cm}^{2}$

Total surface area of the cuboid $=2(l b+b h+l h) \mathrm{cm}^{2}$

$=2(12 \times 9+8 \times 9+12 \times 8) \mathrm{cm}^{2}$

$=2(108+72+96) \mathrm{cm}^{2}$

$=552 \mathrm{~cm}^{2}$