The circumference of a circle can be calculated using the formula:
\[ C = 2\pi r \]
where \( C \) is the circumference and \( r \) is the radius.
Given that the radius \( r \) is 2.5 feet, the formula becomes:
\[ C = 2\pi(2.5) = 5\pi \]
To get a numerical approximation, you can use \( \pi \approx 3.14 \):
\[ C \approx 5 \times 3.14 = 15.7 \text{ feet} \]
Therefore, the circumference of the circle is approximately \( 15.7 \) feet.