I would say the answer is 35.
Let

be the point on the ground to with the 18 foot guy is anchored and

the point on the ground to with the 21 foot guy is anchored.
We can conclude that the <span>the two wires at the points where they are anchored are
21 feet apart. Check the procedures in the picture attached.</span>
The total is 6400, but if subtracted, its 1400
The answer should be 3030.033, since 3*1000 is 3000, 3*10 is 30, 3*1/100 is 0.03, and 3*1/1000 is 0.003.