Question

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

Answer 1

Given,

Diameter of well = 14 m

Radius of well = \(\frac{14}{2}\) = 7 m

depth of well = 8 m

so,

Amount of earth dug out from well = πr²h = \(\frac{22}{7}\) x 7 x 7 x 8 = 1232 m³

This earth is spread out on width of 21 m.

= Area × h = 1232

= π(28² - 7²) x h = 1232

= π x 735 x h = 1232

= h = \(\frac{1232\times 7}{735\times 22}\) = \(\frac{56}{12}\) = 0.533 m = 53.3 cm

Height of embankment = 53.3 cm