In a rectangle, which has width and length, the formula to find the area is:

where A is the area, l is the length and w is the width.
Since we are asked to find the length, we solve for l in the previous equation by dividing both sides by w:

We know the Area A and the width w:

So we substitute these values into the equation to find l:

And thus, we have found that the length of the rectangle is 86 ft.
Answer: 86 ft