To find the circumference \( C \) of a circle, you can use the formula:
\[ C = \pi \times d \]
where \( d \) is the diameter. Given that the diameter is 5.75 miles and using \( \pi \approx 3.14 \), we can calculate the circumference:
\[ C = 3.14 \times 5.75 \]
Now, performing the multiplication:
\[ C = 3.14 \times 5.75 = 18.095 \]
To estimate the circumference to the hundredths place, we round 18.095 to 18.10.
Therefore, the estimated circumference of the circle is 18.10 miles.