1. The problem is to find the square root (racine) of 25. 2. By definition, the square root of a number $x$ is a number $y$ such that $y^2 = x$. 3. We need to find $y$ such that $y^2 = 25$. 4. Observing that $5^2 = 25$, we conclude $y = 5$. 5. Therefore, the square root of 25 is $5$.