Question

9. 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 an
embankment. Find the height of embankment.

Answer 1

Answer:

Given that, height of cylindrical well(h) is 15 m and diameter(d) is 14 m. And width of circular embankment is 7 m.

⇒ radius(r) of well

⇒ outer radius of Embankment(R1) = (7 + 7) = 14 m

⇒ inner radius(r1) = 7 m

Let the height of the embankment be H.

⇒ vol. of well = vol. of embankment

⇒ πr2h = π(R12-r12)H

H = 5 cm