00:02
Okay, so here we have this open top box and we know it's volume and our goal is to find the surface area as a function of a side length so we know that the base is a square so we could label the base with side length a and a and we don't know the height of the box so we can just call it h now we do know the volume is two so we know volume is length times width times height so that would be a times a times h a square times h is two so perhaps we'll end up using that relationship as we go.
00:36
Our goal is to find the surface area, and because there's no top, we have only five surfaces.
00:42
We have the base, which is a times a, and we have four of these sides, which are a times h.
00:52
So the surface area, which i'm going to call capital, i'll call it s, since we're already using an a for something else, surface area is s is going to be the sum of these areas.
01:05
So a squared for the area of the base plus 4 times a times h for the four sides.
01:12
Now we need this to be a function of just the side, not the side and the height.
01:17
So here's where that other equation comes into play.
01:20
Let's take that other equation we got from volume and isolate h.
01:24
We get h equals 2 over a squared, and we can substitute that into the equation.
01:29
We're working with to get rid of the h...