A closed cylindrical tank of radius 7 m and height 3 m is made from a sheet of metal. How much sheet of metal is required?


Given: Radius of cylindrical tank, r = 7m
Height of cylindrical tank, h =3m


The figure of the question is:


 
The total surface area of cylindrical tank, S = 2 π r( h + r)    ............(1)


Putting the values of r and h in equation (1), we get, 


S = 2 ×(22/7)× 7(7 + 3)


S = 2 × (22/7) × 7(10)


S = 2 × 22× 10


S = 440 m2


The total surface area of the cylinder is 440 m


∴  440 m2 of sheet of metal is required.

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