Question

The sum of length, breadth and depth of a cuboid is $12$ cm and its diagonal is $5\sqrt{2}$cm. Find its surface area.

Answer 1

$S=l+b+h;S.A=2(lb+bh+hl)$ & $d=\sqrt{l^2+b^2+h2}$

$\Rightarrow S^2=l^2+b^2+h^2+2(lb+bh+he)=d^2+S.A$

$\Rightarrow S.A.=s^2-d^2$

$\therefore S.A={12}^2-(5\sqrt{2}{)}^2=144-50=94$