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Topic: Real life story problem help
Replies: 5   Last Post: Jul 3, 2005 8:43 PM

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Brian Harvey

Posts: 26
Registered: 12/6/04
Re: Real life story problem help
Posted: Jun 6, 2005 6:12 PM
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jackjohansson@gmail.com writes:
>Now balloons are listed as "12 inches". I am guessing that an
>inflated balloon, and empty space around it when it is put in a large
>room with other balloons would equal maybe 1.25 cubic feet.


If the balloon has a one-foot diameter, that doesn't mean it occupies one
cubic foot when inflated! That would be true if the balloon were cubical in
shape, rather than spherical.

The volume of a cube is 4/3 pi r^3. Your radius is 1/2 foot, so your volume
is pi/6 which is about 0.524 cubic feet.

You're right that there will be some empty air space (depending on how tightly
you cram the balloons in -- you could *force* them to be more or less cubical
(and smaller than advertised) if you really try hard -- but still, you'll need
more balloons, not fewer, than you would if each balloon occupied exactly one
cubic foot.


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