# Math Help - Largest rectangle

1. ## Largest rectangle

I really have no idea where to even begin with this problem. I did some guess and check, but I'm sure there's some method I'm suppose to use that we haven't covered. I understand what it's asking and all, but I'm at a loss as to how to solve it.

Consider the graph of
$
y = \sqrt{x}$

limited to the domain of (0,9).

Find the largest rectangle that can be constructed inside of that shape, with sides parallel to the x- and y-axes and the right edge of the rectangle being the vertical line x = 9.

2. This is a relatively simple calculus problem, but being as this was posted in pre-calc, am I to understand you are not familiar with differentiation?

3. Yeah, I only recently started precalculus, so I don't know much yet.

Edit: Oh, and since we haven't learned differentiation, I'm assuming we're not supposed to use it. We're currently using graphs and maximums and such.