If 9 of Maria's friends ate \( \frac{3}{4} \) of her chocolate cake together, we can find out how much cake each of her friends ate by dividing the amount of cake by the number of friends.
- Calculate the amount of cake each friend ate:
\[ \text{Amount of cake each friend ate} = \frac{\frac{3}{4}}{9} \]
- This can be calculated as:
\[ \frac{3}{4} \div 9 = \frac{3}{4} \times \frac{1}{9} = \frac{3 \times 1}{4 \times 9} = \frac{3}{36} = \frac{1}{12} \]
Thus, each friend ate \( \frac{1}{12} \) of the chocolate cake.