A well with 14m diameter is dug 8m deep. The earth taken out of it has been evenly spread all around it to a width of 21m to form as embankment. Find the height of the embankment.

Explanation

Diameter, `d=14m` and height, `h=8m`

Width of the embankment, `w=21m`

Radius, `r=14/2` = `7m`

Now, outer radius, `R=r+w`

`R=7+21`=`28m`

Volume of earth dug-out = `pir^h`

`22/7xx7xx7xx8` = `1232m^2`

Area of embankment = `pi(R^2-r^2)`

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