Question

A closed metallic cylindrical box is $1.25m$ high and its base radius is $35cm$. If the metal sheet costs $Rs.80$ per $m^2$, then find the cost of the material used in the box ?

Answer 1

$totalsurfacearea=2\pi r^2+2\pi rh=2\pi r(r+h)=2\times 22/7\times 0.35(0.35+1.25)=3.52m^2\therefore cost=801\times 3.52=281.6Rs$