Answer:
5.5
Explanation:
The longest string length is 12 3/4 (12.75)
The two shortest string lengths are 3 and 4 1/4 (4.25)
combine the length of the tow shortest string by adding them together,
3 + 4.25 = 7.25
to find how much longer the longest string you subtract the two numbers,
12.75 - 7.25 = 5.5