Question

How many metal sheet is required to prepare a closed cylindrical Drum of radius 0.7m and height 3m

Answer 1

your question is to find surface area of cylinder
$tsa \: of \: cylinder = 2\pi \: r(r + h)$
r=0.7
h=3
$2 \times \frac{22}{7} \times 0.7(0.7 + 3) \\ = 2 \times 22 \times .1 \times 3.7 \\ 16.28 {m}^{2}$