Question

a well of diameter 3cm is dug 14m deep.the earth taken out of it has been spread evenly all around it in the shape of a circular ring of with 4m to form an embankment. find the height of the embankment​

Answer 1

Solution :

• Height of the well = 14 m.
• Diameter of the well = 3m.
• Therefore, Radius of the well = 3/2 m.

According to question now :

Volume of the earth taken out of the well = πr²h

=> 22/7 × 3/2 × 3/2 × 14

=> 22 × (3/2)² × 2

=> 44 × 9/4

=> 11 × 9

=> 99 cm.

Outer radius of embankment (R) = (3/2 +4)

=> 11/2 m

Now,

Area of embankment = outer area - inner area

=> πR² - πr²

=> 22/7 [(11/2)² - (3/2)²]

=> 22/7 × 112/4

=> 88 m²

Height of the embankment = Volume / Area

=> 99/88

=> 1.125 m

Therefore, the height of the embankment is 1.125 m