let the width of the page be , let the height of the page be .

then, the width of the printed area is ....why is that?

and the length of the printed area is .....why is that?

since the area of the printed material is 200

we have .........this is our constraint equation. we can use this to solve for one variable in terms of the other. for instance, solving for x we get:

now, the area of the page is given by:

...........this is what we want to minimize