Identify whether each of the following is rational or irrational.

Here are the solutions to the problems:

4. Identify whether each of the following is rational or irrational.

• a) $\frac{1}{3}$: This is a fraction of two integers, so it is rational.
• b) $\sqrt{2}$: The decimal representation of $\sqrt{2}$ is non-terminating and non-repeating, so it is irrational.
• c) 0.75: This can be written as $\frac{3}{4}$, so it is rational.
• d) $\pi$: The decimal representation of $\pi$ is non-terminating and non-repeating, so it is irrational.
• e) 7: This can be written as $\