In this course, you will need to rationalize the denominator (make the denominator a rational number) of fractions with radicals in the denominator. Before calculators, there was good reason to rationalize denominators—all calculations had to be done by hand. Consider dividing by , or . What about dividing by , or ? Since was a more useful form, it became the standard form. Use the following method to rationalize the denominator of each radical expression below: .