Answer:
9.55 cm
Step-by-step explanation:
The circumference is also called the perimeter, which is the length of the outline of any shape.
So,
[tex]Perimeter = \pi *diameter\\30 cm = \pi * d\\\\d = \frac{30}{\pi} cm\\\\d=9.54929658551\:cm\\d=9.55\:cm[/tex]
