Final answer:
To find the side length of a square floor from its area, take the square root of the area. The closest side length to the area of 172.3 ft² is 13 ft.
Step-by-step explanation:
The student is asked to determine the length of one side of a square floor given its area in square footage. To find the length of one side of a square when the area is known, one must take the square root of the area. The area of the floor is given as 172.3 ft². The square root of 172.3 ft² is approximately 13.12 ft. Therefore, the closest measurement to the value of one side of the floor is Option 1: 13 ft.