Answer:

12.5 m

Step-by-step explanation:

Given, Inner diameter of the well = 4 m.

Then, radius(r₁) = 2 m.

Depth of the well(h₁) = 10 m.

∴ Volume of the earth dug out from the well = πr₁²h₁

                                                                          = π(2)²(10)

                                                                          = 400π m²

Let the height of the embankment be 'h' m.

Given that earth taken out is spread all around to a height of 4 m.

External radius of the embankment(h₂) = (4 + 2) = 6 m.

Volume of the earth in embankment = πh(r₂² - r₁²)

                                                             = πh(6² - 2²)

                                                             = 32πh

Now,

Volume of well = Volume of embankment

⇒ 400π = 32πh

⇒ h = 12.5 m

Therefore, height of the embankment is 12.5 m.

Hope it helps!

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