Given,
Inside diameter of well = 10 m
Inside radius = \(\frac{10}{2}\) = 5 m
depth of well = 8.4 m
Volume of earth dug out = πr2h = \(\frac{22}{7}\) x 25 x 8.4 m3
Area of embankment formed = π(R2 - r2) = \(\frac{22}{7}\)(17.52 - 102) = 206.25π m2
Height of embankment thus formed = \(\frac{volumr\,of\,well}{area\,of\,embankment}\) = \(\frac{π\times 25\times 8.4}{206.25π}\) = 1.6 m