Question

A cylinder of maximum volume is cut out from a solid metal cuboid of length $20$cm and cross section a square side $14$cm.Find the volume of the metal wasted.

Answer 1

Volume of the solid metal$=14\times 14\times 20=3920$cu.cm

Volume of the cylinder$=\pi r^{2}h=\frac{22}{7}\times 7\times 7\times 20=3080$cu.cm

$\therefore$ Metal wasted$=$ Volume of the solid metal$-$Volume of the cylinder

$=3920-3080=840$cu.cm