Question

3. A 20 m deep well with diameter 7 m is dug and the earth from digging in evenly spread
out to form a platform 22m×14m. find the height of the platform​

Answer 1

Step-by-step explanation:

22*14*h=22/7*7/2*7/2*20

h=22/7*7/2*7/2*20*1/22*1/14

h=20/8=2.5m

Answer 2

Answer:

The shape of the well will be cylindrical as shown in the figure below:

Given:

Depth (h) of well =20 m

Radius (r) of circular end of well =

2

7

m

Area of platform = Length x Breadth =22×14m

2

Assume height of the platform =H

The volume of soil dug from the well will be equal to the volume of soil scattered on the platform.

Volume of soil from well = Volume of soil used to make such platform

⟹πr

2

h = Area of platform x Height of platform

⟹π×(

2

7

)

2

×20=22×14×H

H=

7

22

×

4

49

×

22×14

20

H=

2

5

=2.5m

Hence, the height of such a platform will be 2.5 m.

solution