Assuming you are focusing on the square only, then the answer is 9 inches.
You take the square root of 81 to get 9. Notice how 9^2 = 9*9 = 81. So if you're not familiar with square roots, then think backwards in a sense to get the answer.
Answer: 11) 1/3
12)1/4
13) Likely
Step-by-step explanation:
