Question

a 20 m deep well with diameter 7 cm is dug and the earth from digging is evenly spread out to form a platform 22m by 14 M then the height of the platform is

Answer 1

⇒ Given:- Height (h) of well :- 20m

Diameter (d) :- 7 m

Radius (r) :- 7/2 m

Volume of earth platform :- 22 m by 14m

⇒ To find :- Height of the platform:- ?

⇒ Solution:-

Volume of cylinder of radius 7/2 m and height 20 m

Volume of cylinder :- π(r^2)(h)

= 22/7×(7/2^2)×20 m^3

= 770 m^3

Let the height raised by 22 m × 14 m platform be equal to h metres

Therefore,

Volume of the earth in platform = Volume of the earth taken out of the well

22 × 14 × h = 770

h = 770/22 × 14 m

h = 5/2 m

h = 2.5 m

Hence , the height of the platform is 2.5 m.

Answer 2

Answer:

Step-by-step explanation:

Diamter = 7 m

so, radius = 3.5 m

Earth dug out from (cylindrical) well

=π×r×r×h

=22\7

×3.5×3.5×20

=770m

3 to from platform ...... (cuboidal)

volume of cuboid = l×b×h

770=22×14×h

so, height = 22

770×14=2.5m