To find the area of a square scarf, you use the formula for the area of a square, which is:
\[ \text{Area} = \text{side length}^2 \]
In this case, the side length of the scarf is \( \frac{3}{4} \) yard. Therefore, we compute the area as follows:
\[ \text{Area} = \left(\frac{3}{4}\right)^2 \]
Calculating this, we have:
\[ \left(\frac{3}{4}\right)^2 = \frac{3^2}{4^2} = \frac{9}{16} \]
Thus, the area of the scarf is:
\[ \frac{9}{16} , \text{yd}^2 \]
So, the area of the scarf is \(\frac{9}{16}\) in simplest form.