Step-by-step explanation
So we have a ratio of 3 feet to 63 inches and we must write it as a fraction. The first thing to do is convert feet to inches so we have both parts in the same unit. According to the table there are 12 inches in 1 foot so 3 feet is equivalent to:

So the ratio is 36 inches to 63 inches. In order to express it as a fraction we must take the left part and divide it by the right part:

Answer
Then the answer is 4/7.