To find the circumference of a circle, you can use the formula:
\[ C = \pi \times d \]
where \( C \) is the circumference and \( d \) is the diameter. Given that the diameter \( d = 5.75 \) miles and using \( \pi \approx 3.14 \):
\[ C = 3.14 \times 5.75 \]
Now let's perform the multiplication:
\[ C = 3.14 \times 5.75 = 18.095 \]
Rounding to the hundredths place, the circumference is:
\[ C \approx 18.10 \text{ miles} \]
So, the estimated circumference is 18.10 miles.