Question

A 20m deep well with diameter 14 cm is dug up and the earth taken out from digging is evenly spread out to a width of 3 m to form an embankment. Find the height of the embankment.

Answer 1

Answer:

The well dug is in the shape of a cylinder.

Radius of the well =

2

20

=10m

Volume of a Cylinder =πR

2

h

Hence, Volume of earth taken out from the well =π×10×10×14=1400πm

3

The embankment would form a circular ring with internal radius same as radius of the well =10m

And external radius =10+5=15m

Area of embankment =π×(15

2

−10

2

)=π×(1510)×(15+10)=125π

Height of the embankment =

Area

Volume

=

125π

1400π

=11.2m