A well of diameter 4 m is dug 14 m deep. The earth taken out is spread evenly all around the well to form a 40 cm high embankment. Find the width of the embankment.
Depth (h1) of the well = 14 m
Radius (r1) of the circular end of the well =`4/2` m = 2 m
Height (h2) of embankment = 40 cm = 0.4 m
Let the width of embankment be x.
From the figure, it can be observed that the embankment will be cylindrical in shape having outer radius (r2) as (2 + x) m and inner radius (r1) as 2 m.
Volume of earth dug from the well = Volume of earth used to form embankment
⇒x=10 (Because x cannot be negative)
Therefore, the width of the embankment will be 10 m.