

Ask HN: Solve this FoundersFund problem - Edmond

A sphere has a diameter of 2,160 meters. How many meters long is “Unit X” if the surface of the sphere, measured in square Units X is equal to the volume of the sphere measured in cube Units X? Round to the nearest whole number, and enter the number only.
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kenrose
Radius r = 1080 meters.

Volume of a sphere = (4/3) * pi * r^3

Surface area of a sphere = 4 * pi * r^2

We want to find x, some unit of measure.

The volume of the sphere in units of x^3 is:

((4/3) * pi * r^3) / x^3

The surface area of the sphere in units of x^2 is:

(4 * pi * r^2) / x^2

The problem states these are equal. So:

((4/3) * pi * r^3) / x^3 = (4 * pi * r^2) / x^2

(1/3) * r = x

360 = x

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markmassie
1741

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Edmond
nope...try a little harder :)

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markmassie
It's early...

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s3b
360

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Edmond
correct..now go ahead and submit your business plan :)

