Question

A well of 12m deep and 7m diametere А is dug and the earth taken out of it is deposited around the well in the shape embankment of width 3.5m. find the height of embankmont?​

Answer 1

Answer:

h = 4 m

Step-by-step explanation:

Volume of the cylindrical well = Volume of the hollow cylindrical embankment

πr²h₁ = πR²h - πr²h

πr²h₁ = πh (R² - r²)

r²h₁ = h (R - r )(R + r)

h = [(r²h₁)/(R - r)(R + r)]

h = [((3.5)² × 12)/(7 - 3.5)(7 + 3.5)]

= 147/(3.5)(10.5)

= 4 m