1. The problem is to find the square root of 4. 2. The square root of a number $x$ is a value $y$ such that $y^2 = x$. 3. For $x = 4$, we want to find $y$ such that $y^2 = 4$. 4. The numbers that satisfy this are $y = 2$ and $y = -2$ because $2^2 = 4$ and $(-2)^2 = 4$. 5. By convention, the square root symbol $\sqrt{\cdot}$ denotes the principal (non-negative) root. 6. Therefore, $\sqrt{4} = 2$. Final answer: $\boxed{2}$