Step 1 :Let the width of the printed area be \(x\) inches and the height be \(y\) inches. Then the area of the printed area is \(xy = 27\) square inches.
Step 2 :Since there is a 3-inch margin on the top and bottom, the total height of the page is \(y + 2 \times 3 = y + 6\) inches.
Step 3 :Similarly, since there is a 4-inch margin on each side, the total width of the page is \(x + 2 \times 4 = x + 8\) inches.
Step 4 :So, the total area of the page is \((x + 8)(y + 6)\) square inches.
Step 5 :We want to minimize this total area. To do this, we can express \(y\) in terms of \(x\) using the equation \(xy = 27\), which gives us \(y = \frac{27}{x}\).
Step 6 :Substituting \(y = \frac{27}{x}\) into the equation for the total area gives us \((x + 8)\left(\frac{27}{x} + 6\right)\).
Step 7 :We can simplify this to \(27 + 6x + \frac{216}{x} + 48\), which simplifies further to \(6x + \frac{216}{x} + 75\).
Step 8 :This is a function of \(x\) that we want to minimize. To find the minimum of a function, we can take its derivative and set it equal to zero.
Step 9 :The derivative of \(6x + \frac{216}{x} + 75\) with respect to \(x\) is \(6 - \frac{216}{x^2}\). Setting this equal to zero gives us \(6 - \frac{216}{x^2} = 0\).
Step 10 :Solving this equation for \(x\) gives us \(x = \sqrt{36} = 6\).
Step 11 :Substituting \(x = 6\) into the equation \(y = \frac{27}{x}\) gives us \(y = \frac{27}{6} = 4.5\).
Step 12 :So, the dimensions that minimize the amount of paper used are \(x + 8 = 6 + 8 = 14\) inches for the width and \(y + 6 = 4.5 + 6 = 10.5\) inches for the height.
Step 13 :\(\boxed{14, 10.5}\) are the dimensions that minimize the amount of paper used.