In a parallelogram, the diagonals bisect each other. This means that the point where the diagonals meet (point A in your case) is the midpoint of each diagonal.
Given that diagonal WY measures 7 centimeters, we can find the length of AW by recognizing that point A is the midpoint of WY.
Since A is the midpoint, the length of AW is half the length of WY:
\[ AW = \frac{WY}{2} = \frac{7 \text{ cm}}{2} = 3.5 \text{ cm} \]
Therefore, the length of AW is 3.5 centimeters.