Question

How much metal sheet is required to make an open cylindrical tank of radius 4.2 metre and height 15 metre

Answer 1

Radius = 4.2 m
Height = 15 m
Metal sheet required = Curved surface area of Cylinder
Curved surface area of Cylinder = 2$\pi rh$
                                                   = 2 X 3.14 X 4.2 X 15
                                                   = 395.64 m^2
Therefore, Metal sheet required = 395.64 m^2

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Answer 2

curved surface area of cylinder = 2πrh
= 395.64 metre square.
area of base = πr^2 = 55.38 metre square
total sheet required = 395.64+55.38
= 451.02 metre square