To represent the total number of students \( S \) taking yoga, you can use the following equation:
\[ S = 11C \]
In this equation:
- \( S \) is the total number of students.
- \( C \) is the number of classes.
- Each class has 11 students, so you multiply the number of classes \( C \) by 11 to get the total number of students \( S \).