Question

2 cubes each of volume 64cmsq. find SA of resulting cuboid

Answer 1

Volume of cube = 64 cm^3

Edge of cube = cube root 64

= 4 cm

Length of cuboid formed = 8 cm

Width of cuboid = 4 cm

Height of cuboid = 4 cm

TSA = 2( 8*4+4*4+4*8)

= 2(32+16+32)

= 2*80

= 160 cm^2

Answer 2

Volume of a cube
$= {side}^{2}$
Therefore
$side = \sqrt{64}$
$side = 8$
Now let us first find the surface area of one cube
Surface area of a cube
$= 6 \times {side}^{2}$
$= 6 \times {8}^{2}$
$= 6 \times 64$
$= 384 {cm}^{2}$

We need surface area of the two cubes that is cuboid
Therefore surface area
$= 384 \times 2$
$= 768 {cm}^{2}$
NOTE:
Two of the sides would join and would go in the interior
Therefore
Surface area of cuboid
$= 768 - {2 \times {side}^{2} }$
$= 768 - 2 \times 64$
$= 768 - 128$
$= 640 {cm}^{2}$
Hope it helps! ☺