A well with 10 m inside diameter is dug 8.4 m deep. Earth taken out of it is spread all around it to a width of 7.5 m to form an embankment. Find the height of the embankment.
Given,
Inside diameter of well = 10 m
Inside radius = 
depth of well = 8.4 m
Volume of earth dug out = 
Area of embankment formed = 
Height of embankment thus formed = 
40