Monday, January 30, 2012

How do you calculate the percentage of the volume?

The question is this: Earth has a thin outer layer that averages 24km thick. Earth's diameter is about 12,270km. What is the percentage of the volume of Earth is the crust?How do you calculate the percentage of the volume?
The volume varies with the cube of the radius.



Radius with crust is 6135.

Crust is 24.



So the crust represents (24/6135)^3 of the whole.

24/6135 = 0.00391



The cube of that is: 5.9867 e-8

or 0.000000059867



A reasonable, but not exact, analogy would be wrapping

a sheet of paper around a basketball.

That's how thin it is.



(You could use V = 4/3 pi r^3 to calculate volume

with and without the crust, but then the 4/3 pi

cancels from both, so I just skipped introducing them

in the first place.)

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