Q13 of 51 Page 13

A well of diameter 3 m dug 14 m deep the earth was taken out of it has been spread evenly all around it in the shape of a circular ring of width 4 m to form an embarkment. Find the height of embarkment.

Given: diameter of well = 3 m


Depth of well = 14 m


Width of embankment = 4 m


To find: Height of embarkment.


Formula Used:


volume of the cylinder = πr2h


Explanation:



Height of the well = 14 m


Diameter of the well = 3 m


So, radius =


Let height of embankment be “h” m.


As earth is taken out from the well and has been spread to make a cylindrical embankment,


⇒ Volume of the earth taken out = volume of the well = πr2h


Volume of the earth taken out = πr2h


=




Outer radius of the embankment = R




Area of the embankment = Outer area – Inner area


= πR2 -πr2


= π(R2 -r2)







Height of the embankment =




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