Answer:
[tex]r$\approx$2.9[/tex]
Step-by-step explanation:
The equation for circumference is:
[tex]C=2\pi r[/tex]
We can plug 18 cm in for C:
[tex]18=2\pi r[/tex]
Divide both sides by 2
[tex]9=\pi r[/tex]
Divide both sides by [tex]\pi[/tex]
[tex]r$\approx$2.9[/tex]
