To find the diameter of a circle from its circumference, you can use the formula for the circumference \( C \) of a circle, which is:
\[ C = \pi d \]
where \( d \) is the diameter and \( \pi \) (approximately 3.14 or more precisely 3.14159) is a constant.
Given that the circumference \( C \) is 15.7 feet, you can rearrange the formula to solve for the diameter \( d \):
\[ d = \frac{C}{\pi} \]
Substituting in the value of the circumference:
\[ d = \frac{15.7}{\pi} \approx \frac{15.7}{3.14159} \approx 5.003 \]
Thus, the diameter of the circle is approximately 5.00 feet.