Question

A cuboidal box of dimension 2m X 3m X 1.5m is to be painted except its bottom.

Calculate how much area of the box has to be painted.​

Answer 1

$\large\green{\underline{\underline{\mathcal{Given,}}}}$

• $\sf{Length\:of\:the\:box,l=3\:m}$
• $\sf{Breadth\:of\:the\:box,b=2\:m}$
• $\sf{Height\:of\:the\:box,h=1.5\:m}$

$\large\green{\underline{\underline{\mathcal{We\:know\:that,}}}}$

• $\sf{Surface\:area\:of\:a\:cuboid=2(lb+lh+bh)}$

But here the bottom part is not to be painted.

But here the bottom part is not to be painted.So,

Surface area of box to be painted,${\bf{=lb+2(bh+hl)}}$

$\large{\bf{=3×2+2(2×1.5+1.5×3}}$

$\large{\bf{=6+2(3+4.5)}}$

$\large{\bf{=6+2×7.5)}}$

$\large{\bf{=6+15}}$

$\large{\bf{=21}}$

$\boxed{\mathscr{\green{Hence,the\:required\:answer\:is\:21\:\:m^2}}}$