This problem needs us to solve.
There are 7 stay cable lengths in total. The length of each stay cable can be calculated by Pythagoras' law. The length is 3 feet and the height is 2 feet, that is, 20 feet. Divided by 7 equals 20/7 feet.
Let the cable-stayed length be d: (20/7) 2+3 2 = d2.
D=29/7
Then the total length of the stay cable is 6×D=6×29/7=29 feet, which is 2 feet 9 feet long.
So the total length of the vine is 2 feet 9 feet.