Math, asked by dannydant, 1 year ago

a well of inner diameter 14m is dug to a depth of 12m . Earth taken out of it has been evenly spread all around it to a width of 7m to form an embankment . Find the height of the embarkment so formed

Answers

Answered by monujha1106
4
Hey
_________________

•volume of well or earth dug out = πr^2h
diameter = 14m , radius =14/2=7m
depth / height = 15m
•now volume = 22/7×(7)^2×15
=105×22

•volume of embankment =π(R^2-r^2)×h
outer radius (R) = outer width + inner radius
= 7+7=14m
inner radius(r) = 7 m
height = ?
•volume = 22/7 ( 14^2-7^2)×h
=22/7×196-49×h
=22/7×147×h
=22×21×h

•earth taken out of well is spread over all around it forming a embankment

•volume of well = volume of embankment

105×22=21×22×h
105×22/21×22 = h
105×22/462=h
h=5m

hence height is 5 m

hope helped
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dannydant: answer is wrong its 4 m
monujha1106: OK I sorry bro
Answered by siddhartharao77
20

Answer:

4m

Step-by-step explanation:

(i) Volume of well:

Diameter = 14 m.

Then radius = 7 m.

Height = 12 m.

Volume of cylinder = πr²h

                                = (22/7) * (7)² * 12

                                = 1848 m³



(ii) Volume of embankment:

Inner diameter = 14 m.

Internal radius r₁ = 7 m

External radius = r₂ = 14 m.

Now,

∴Volume of cylinder with internal radius = πr₁²h

                                                                   = π(7)²h


∴ Volume of cylinder with external radius = πr₂²h

                                                                     = π(14)²h


∴ Volume of cylinder = πh[14² - 7²]

                                   = πh[196 - 49]

                                   = 147πhm³

                                   = 147(22/7)h

                                   = 462 m³


So, volume of embankment = 462m³.

Now,

Volume of well = volume of embankment

⇒ 1848 = 462h

⇒ h = 4 m.


Therefore, Height of the embankment = 4 m.


Hope it helps!


ArshiaKhan: superb ❤sir
siddhartharao77: Thank you
monujha1106: no problem
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