Question

Find the length of a cuboid whose breadth and height are 4 cm and 6 cm respectively and total surface area is 408 $c{m}^2$ is.

• A. 8 cm
• B. 12 cm
• C. 16 cm
• D. 18 cm

Answer 1

The correct option is D 18 cm

Total surface area of a cuboid is given by $2(lb+lh+bh)$
where l, b and h represents the length, breadth and height respectively.

Since area is equal to 408 $c{m}^2$
$\Rightarrow 2(lb+bh+lh)=408$
$\Rightarrow lb+bh+lh=204$
$\Rightarrow 4l+24+6l=204$
$\Rightarrow 10l=204-24=180$
$\Rightarrow l=18cm$

Therefore, length of the cuboid = 18 cm