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Volume vs Area Problem

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Volume vs Area Problem

by hijazim » Sun Mar 01, 2009 6:00 am
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I guess there is something wrong with this question.

First, Volume of cube = Area of surface x Height

So to know the Volume we should know the height.
If we assume that height=r then volume = 54r^3

But the OA is D. that is volume of cube = 27r^3 assuming that height=27r^3/54r^2 => hieght= r/2.

Any help guys!!!!
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by Uri » Sun Mar 01, 2009 6:22 am
vol of a cube= a^3, where a is the length of a side
surface area of a cube= 6*(a^2)
it's given, 6*(a^2)=54*(r^2)
thus, a=3*r
so, volume= 27*(r^3)
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Senior | Next Rank: 100 Posts
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by hijazim » Sun Mar 01, 2009 6:39 am
thx Uri.. I guess my problem was that i assumed the surface area of cube = area of square while it is aqual to 6 x area of the square

Thanks a lot.
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