Which of the following numbers is irrational?

Explanation

1. 01

   $\sqrt{49} = 7$, an integer, so it is rational.

2. 02

   $\frac{22}{7}$ is a ratio of integers, and $0.\overline{3} = \frac{1}{3}$; both are rational.

3. 03

   $\sqrt{12} = 2\sqrt{3}$, and $\sqrt{3}$ cannot be written as a ratio of integers, so $\sqrt{12}$ is irrational.