word problem

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Luke53
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word problem

Postby Luke53 » Wed Aug 17, 2011 3:09 pm

Hi, can anyone help me with this problem.

The radius of a rectangular cone is "r", and height "h", by what value "x" must "r" be increased and "h" be decreased to keep an identical volume?

Thanks.

Luke.

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little_dragon
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Re: word problem

Postby little_dragon » Wed Aug 17, 2011 8:03 pm

Luke53 wrote:The radius of a rectangular cone is "r", and height "h", by what value "x" must "r" be increased and "h" be decreased to keep an identical volume?

i think U do like this:
Vold=(1/3)(2pi*r)(h)
Vnew=(1/3)(2pi)(r+x)(h-x)
put them equal
div out the 1/3 & 2pi
rh=(r+x)(h-x)
rh=rh+xh-rx-x^2
solve for x
:wave:


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