To find the diameter of a circle given the circumference, you can use the formula for the circumference of a circle:
\[ C = \pi \times d \]
where \( C \) is the circumference and \( d \) is the diameter. Rearranging this formula to solve for the diameter gives:
\[ d = \frac{C}{\pi} \]
Given that the circumference \( C \) is 15.7 ft and using \( \pi \approx 3.14 \):
\[ d = \frac{15.7}{3.14} \approx 5.00 , \text{ft} \]
Therefore, the diameter of the circle is 5.00 ft.