# What dimensions should you make a rectangular poster of total area 72 square inches in order to maximize the printed area if it is required that the top and bottom margins be 2 inches and the side be 1 inch?

##### 1 Answer

Let's call the width of the poster

#### Explanation:

It's fairly easy to see that, because the surface area is

Printable in

Printable in

Total printable area:

It's now time to substitute the

For the optimum we need to set the deravative of

Re-arrange and set to

This is the width. The height is:

**Answer** : Width is 6", height is 12".

**Check** :

Total area printed is

Graph of the area-function

graph{80-4x-144/x [-36, 112.2, -11.25, 62.75]}