1. The problem is to find the square root of 144. 2. The square root of a number $x$ is a value $y$ such that $y^2 = x$. 3. We want to find $y$ such that $y^2 = 144$. 4. Since $12^2 = 144$, the square root of 144 is 12. 5. Therefore, $\sqrt{144} = 12$.