Final answer:
The length of Square P is 4 times as great as the length of Square Q.
Step-by-step explanation:
The length of Square P is 4 times as great as the length of Square Q.
To compare the areas of the two squares, we square the ratio of their lengths. Since the area of Square P is 16 times as great as the area of Square Q, the length ratio squared is 16. Therefore, the length of Square P is 4 times as great as the length of Square Q.