This type of word problem involves the use of known formulas. Usually we used one of the formulas for either
volume or surface area, depending on what information was given, to solve for the
radius or
height of the cylinder. In one case, when the
height and
surface area are given, we were required to solve a
quadratic equation for the value of
r. If that
expression had not factored easily, we would have had to used the
quadratic formula.
Once values of both r and h were known, the
volume and
surface area formulas were used. These problems require careful arithmetic since it is often difficult to determine whether or not our answers are reasonable. Notice that the
surface area formula can be written in more than one way. Using more than one of these can serve as a way to check answers or make a calculation easier.