Question

A well of inner diameter 21m is dug to a depth of 15m.The earth dug out was evenly spread all around it to a width of 3.5m to form an embankment formed.(The outer radius of the embankment is 10.5+3.5 = 14m and its inner radius is 10.5m.)​

Answer 1

Step-by-step explanation:

Answer

Volume of the earth=πr

2

H where H is the depth of the well.

=

7

22

×3.5

2

×22.5

=866.25cubic metre.

This earth is used to make the embankment.

Volume of earth(embankment)=πR

2

H−πr

2

h

⇒

7

22

×(10.5+3.5)

2

h−

7

22

×(3.5)

2

h=866.25

⇒

7

22

×14×14h−

7

22

×3.5×3.5h=866.25

⇒616h−38.5h=866.25 on simplification

⇒577.5h=866.25

⇒h=

577.5

866.25

=1.5m

∴ The height of embankment=1.5m

Answer 2

Answer:

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