To find the total number of students at Oakdale Middle School, we can set up a proportion. We know that 408 students represent 60% of the total number of students.
Let \( x \) be the total number of students at the school. We can create the equation:
\[ 0.60x = 408 \]
To find \( x \), we can divide both sides by 0.60:
\[ x = \frac{408}{0.60} \]
Calculating the right side:
\[ x = 680 \]
So, the total number of students at Oakdale Middle School is 680.