Answer: The correct option is (D) 8.89 feet.
Step-by-step explanation: Given that a square rug covers 79 square feet of floor.
We are to find the approximate length of one side of the rug to the nearest hundredth foot.
Let, x feet represents the length of one side of the square rug.
Then, according to the given information, we have

Since the length of the side of the square rug can not be negative, so
x = 8.888 feet.
Rounding to the nearest hundredth foot, we get
x = 8.89 feet.
Thus the approximate length of one side of the rug is 8.89 feet.
Option (D) is correct.