Area of the sheet used to make the tank = total surface area of the cylinder = 2
r(r+h) = 2 x 22/7 x 63 x 263 = 104148 sq. cm.
6 is the anwser to ur question
No; we have
. Substituting these into the DE gives

which reduces to
, true only for
.
You can write i I as 1/4 of a 3rd