For this problem, the total length of fencing is equivalent to the perimeter of a rectangle. The formula for the perimeter of a rectangle is written below:
P = 2L + 2W
where L and W are the length and width dimensions
From the relationship described,
P = 350,350 ft
W = 2/3 L
Substituting this to the perimeter equation:
350,350 = 2L + 2(2/3 L)
Solving for L,
L = 105,105 ft
W = (2/3)(L) = (2/3)(105,105) = 70,070 ft