Classify the following numbers as rational or irrational: 2: Simplify each of the following expressions: 3. Recall, π is defined as the ratio of the circumference (say c) of a circle to its diameter (say d). That is, π = c/d . This seems to contradict the fact that π is irrational. How will you resolve this contradiction? When we measure the length of a line with a scale or with any other device, we only get an approximate rational value, i.e. c and d both are irrational. <!--[if !supportLineBreakNewLine]-->∴ c/d is irrational and hence π is irrational. Thus, there is no contradiction in saying that π is irrational . 4. Rationalise the denominators of the following: