Final answer:
The circumference of a circle with a diameter of 18 cm is approximately 56.52 cm.
Step-by-step explanation:
The circumference of a circle can be found using the formula C = πd, where C is the circumference and d is the diameter of the circle.
Given that the diameter of the circle is 18 cm, we can substitute this value into the formula:
C = π(18 cm)
C ≈ 3.14 * 18 cm
C ≈ 56.52 cm
Therefore, the circumference of the circle is approximately 56.52 cm.