Question

A well with 12 m inside diameter is dug 21 m deep.
Earth taken out of it is spread all around to a width of 6 m to form an embankment. Find the height of
the embankment.​

Answer 1

The height of Embankment would be 7 m.

1) The volume of earth taken out from digging the well = πr²h

r = 12/2= 6 m.

h= 21 m.

volume = π(6)²(21)

2) Let the height of Embankment be h°.

3) Volume of Embankment would be π(12)²(h°) - π(6)²(h°) = 108πh°.

4) 108πh° = π(6)²(21)

5) h° = (6)²(21)/108 = 7 m.