Question

Two cubes each of volume 8 cm3 are joined end to end, then what is the surface area of resulting cuboid

Answer 1

given
volume = 8cm^3

volume of cube =
${s}^{3} \\ 8 = {s}^{3} \\ \sqrt[3]{8} = s \\ 2cm \: = s$
surface area of resulting cuboid=2( total sauface area of cube)-2(area of square)
$2(6 {s}^{2} ) - 2 {s}^{2} \\ = 12 \times {2}^{2} - 2 \times {2}^{2} \\ = 12 \times 4 - 2 \times 4 \\ = 48 - 8 \\ = 40 {cm}^{2}$

Answer 2

Side of the cube, a = $\bf\huge\sqrt[3]{8}$  = 2 cm

Now, the length l of cuboid  = 4 cm

breadth, b = 2 cm

height, h = 2 cm

Surface area of cuboid

= 2(l × b + b × h + h × l)  

= 2(4 × 2 + 2 × 2 + 2 × 4)

= 2 × 20

= 40 cm^2