Two cubes each of side 8 cm are joined end to end find the volume of the resulting cuboid

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Two cubes, each of volume 512 cm 3 are joined end to end, find the surface area of the resulting cuboid.

Solution

Volume of each cube = 512 $c{m}^3$
$\therefore$ Edge of cube (a) = $\sqrt[3]{3512}=\sqrt[3]{38\times 8\times 8\times cm}$
= $\sqrt[3]{38^3}$ = 8 cm Now by joining the two equal cubes of side 8 cm, the length of so formed cuboid (l)

= $2\times 8=16cm$

Breadth (b) = 8 cm and height (h) = 8 cm

$\therefore$ Surface area = $2(l\times b+b\times h+h\times l)$

= $2(16\times 8+8\times 8+8\times 16)c{m}^2$
= $2(128+64+128)c{m}^2$
= $2\times 320=640c{m}^2$

Mathematics

RD Sharma

Standard VIII