word problem

[Luke53]

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.

[little_dragon]

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:
V_old=(1/3)(2pi*r)(h)
V_new=(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