Question

A well of diameter 3m is dug 21 m deep.The earth taken out of it is spread evenly all around it to a width of 8m to form an embankment .Find the height of the embankment.

Answer 1

this is your answer .....................

Answer 2

Answer:

0.5235 m.        

Step-by-step explanation:

Diameter of well = 3 m

Radius of well = Diameter/2 = 3/2 =1.5 m

Depth of well = 21 m

Well is in the shape of cylinder  

Volume of well = $\pi r^{2} h$

                  $= 3.14 \times 1.5 ^{2} \times 21$

                   $= 148.365 m^3$

Radius of embankment = Radius of well + width

                                             = 1.5 + 8

                                             = 9.5 m

Since , Embankment is in the shape of cylinder .  

So, volume of embankment =  $\pi r^{2} h$

                                              $= 3.14 \times 9.5^{2} \times h$

                                             $= 283.385h$

Since the earth is taken out from the well is used to make embankment .

So, volume will be equal.

$\Rightarrow 148.365 =283.385h$

$\Rightarrow \frac{148.365}{283.385}=h$

$\Rightarrow 0.5235=h$    

Hence the height  of the embankment is 0.5235 m.