Question

It is required to make a closed cylindrical tank of height 1 m and base diameter 140 cmfrom a metal sheet. How many square metres of the sheet are required for the same?

Answer 1

Metal sheet required to make a closed cylindrical tank = Curved surface area of cylinder + 2*Base area of cylinder
`= 2pirh+2pir^2=2pir(r+h)`
Here, `r = d/2 = 140/2 = 70cm = 0.7m`
`h = 1m`
So, required area, `A = 2**22/7**0.7(1+0.7)`
`A = 4.4**1.7 = 7.48m^2`
So, `7.48m` square metres of the sheet are required to make the given cylinder.