Final answer:
The simplified ratio of the pool's length to its width in feet is 17:12, which is option C.
Step-by-step explanation:
To simplify the ratio of the length to the width of the rectangular swimming pool, we need to convert the width to the same unit of measure as the length. Since we are using the larger unit, we will convert inches to feet. There are 12 inches in a foot, so the width of the pool in feet is 72 inches ÷ 12 inches/foot = 6 feet. The length is 8.5 feet. The simplified ratio, therefore, is 8.5:6, which when both terms are multiplied by 2 to eliminate the decimal, becomes 17:12. Thus, out of the options provided, the correct answer is Option C, 17:12.