A rectangular page is designed to contain 72 square inches of print. The margins at the top and bottom of the page are each 4 inches deep. The margins on each side are 2 inches wide. The dimensions of page are such that the least possible amount of paper is used.
Thus the width of the page is inches, its height is inches, its total area is square inches. There's a whole lot of white space on that page, its minimum area not withstanding!
Hint: Let $x$ be the width of the printed part of the page, and $72/x$ its height. Plot the area as a function of $x$. Also think about your expectations. Do you expect the page to be taller than it's wide, or vice versa? Why?