To find out how much of the full can of paint Layla used, we need to calculate \( \frac{2}{3} \) of \( \frac{3}{4} \).
We can do this with the following multiplication of fractions:
\[ \frac{3}{4} \times \frac{2}{3} \]
When we multiply fractions, we multiply the numerators together and the denominators together:
\[ \frac{3 \times 2}{4 \times 3} = \frac{6}{12} \]
Next, we can simplify \( \frac{6}{12} \):
\[ \frac{6}{12} = \frac{1}{2} \]
So, Layla used \( \frac{1}{2} \) of a can of paint.