Answer:
The length of the long side of the rectangle is 38 ft.
Explanation:
If we test out all possible factors, we will see that 15 x 38 is the most fitting.
Perimeter: 15 + 15 + 38 + 38 = 106 ft.
Area: 15 x 38 = 570 square ft.
38 ft. is the measurement of the long side and 15 ft. is the measurement of the smaller side.