Question

3 cubes of edges 8cm. are joined end to end . find surface area of resulting cuboid

Answer 1

Edge of the 3 cubes = 8 cm
volume of 1 cube = a³
= 8³
= 512 cm³
volume of cuboid formed = 3 × 512 = 1536 cm³
Dimensions of the cuboid,
length = 8 + 8 + 8 = 24 cm
breadth = 8 cm
height = 8 cm
Total surface area of the cuboid = 2 ( lb + bh + hl )
= 2 ( 192 + 64 + 192 )
= 896 cm²

Answer 2

$\large\mathsf\red{Dimensions \ of \ resulting \ Cuboid \ -}$

$\mathsf{Total \ Length, \ l \ = \ 8 + 8 + 8 \ = \ 24 \ cm}$

$\mathsf{Height \ and \ Breadth \ remain \ same.}$

$\mathsf{Height, \ h \ = \ Breadth, \ b \ = \ 8 \ cm}$

$\mathsf{Using \ formula}$

$\mathsf\purple{T.S.A. \ of \ Cuboid \ = \ 2(lb + bh + hl)}$

$\mathsf{= \ 2 [(24)(8) + (8)(8) + (8)(24)]}$

$\mathsf{= \ 2 (192 + 64 + 192)}$

$\mathsf{= \ 2 × 448}$
$<marquee>$
$\huge\mathsf\blue{\boxed{= \ 896 \ cm^2}}$