To determine the circumference of any circle we need to use the following formula:
[tex]C=2\cdot\pi\cdot r[/tex]
Where r is the radius, which is half of the diameter. For this problem we have a pool with diameter equal to 18 feet, therefore the circumference is:
[tex]\begin{gathered} C=2\cdot3.14\cdot\frac{18}{2}=2\cdot3.14\cdot9 \\ C=56.52\text{ ft} \end{gathered}[/tex]
The circumference of the pool is approximately 57 feet.
