Answer:
8.88 feet
Step-by-step explanation: Since it is a square all the sides equal the same number. You may not know how to use square roots yet but, I will show you how they are helpful. The square root of a number is when the 2 numbers being multiplied together are the same. For example, 3*3 is 9. The square root of 9 is 3 because when you multiply 3 and 3 together you get 9. For your problem since all the problems start with 8.8 we know it is bigger than 8 and less than 9 because the square root of 8 is 64 and the square root of 9 is 81. Since 79 is closer to 81 then it is to 64 we know 8.86 and 8.87 won't work because they are too small. From here the best way to figure it out is by trial and error if you are not allowed to use a calculator. So try 8.88 times 8.88 and 8.89 times 8.89. But if you are allowed to use a calculator (a scientific calculator) type in 79. There should be a button that looks like . If you press it it will give you the square root of 79 (which is what you are looking for).