<PRE><B>Question 698706</B>
The surface area of a cylinder is equal to the sum of the areas of the circles on the top and bottom of the cylinder and the area around the cylinder.&lt;br&gt;

The area of a circle is {{{pi*r^2}}}, where r = 18, so {{{pi*18^2 = 324*pi}}} is the area of each circle.&lt;br&gt;

The area of the section between the circles is a bit trickier. You can think of this section as a rectangle rolled up into a cylindrical shape. This rectangle has a height of 48, and a width equal to the circumference of the circle, which is&lt;br&gt;

{{{2*pi*r = 2*pi*18 = 36*pi}}}.&lt;br&gt;

The area of this rectangle is equal to the height times the width, which is {{{48*(36*pi) = 1728*pi}}}.&lt;br&gt;

The sum of the area of the three parts is {{{324*pi + 324*pi + 1728*pi = 2376*pi}}}.&lt;br&gt;

The surface area is 2376*pi = 7464.424 square inches.</PRE>