*Note:* I edited my original response to this question because what I said originally wasn't quite right. I'll chalk that up to being tired from my long drive yesterday.

Excellent, our first post! Tyler, thanks for labeling the thread in a useful manner.

The formula $V=\pi r^2 h$ will give the volume of a cylinder of radius $r$ and height $h$, but we need to express the volume in terms of the single variable $r$. To eliminate the variable $h$, we need to use the information about the surface area. To find the surface area, you need to add the area of the side and the area of the top and bottom and then set that equal to 100. Next, solve for $h$ and see if you can go from there.

On a different note, notice how nice the formula for the volume of the cylinder is. One of the benefits of using this wiki is that it plays nice with $\LaTeX$, which is one of the standards for typesetting mathematics. What I actually typed was

The double brackets indicate a command for the wiki and the dollar signs indicate that the wiki should render some mathematical notation. I also put the variables in $\LaTeX$-mode using expressions like

which makes them look just like the variables in the corresponding equation. In general, variables are typeset in italics. Many commands in $\LaTeX$ are of the form `\some-command`. For example, $\pi$ is typeset with `\pi` (assuming that it is enclosed with double brackets and dollar signs). Throughout the semester, I will provide you with more and more information about $\LaTeX$. In the meantime, feel free to take a look at the quick LaTeX guide that I put together. Give it a try. Another wonderful thing about the wiki is that we can fix any mistakes; so feel free to experiment.