To determine how many costumes Scott can make, we need to divide the total amount of purple fabric he has by the amount of fabric needed for each costume.
Scott has 12 yards of purple fabric and each costume requires \( \frac{3}{4} \) yard of fabric.
The calculation is:
\[ \text{Number of costumes} = \frac{\text{Total fabric}}{\text{Fabric per costume}} = \frac{12}{\frac{3}{4}} \]
To divide by a fraction, we can multiply by its reciprocal:
\[ = 12 \times \frac{4}{3} \]
Now, calculate \( 12 \times \frac{4}{3} \):
\[ = \frac{12 \times 4}{3} = \frac{48}{3} = 16 \]
Therefore, Scott can make 16 costumes.