Hello there!
Now, the formula to find the circumference of a circle is C = 2[tex] \pi [/tex]r. Now, since the circumference is 18[tex] \pi [/tex], all we have to do is to divide 18 by 2 to find the radius!
The radius of the circle is 9 cm, since 18/2 = 9. However, this is the radius. We need the diameter.
Multiply 9 by 2 to find the diameter. 9 · 2 = 18. So the answer is B. 18 centimeters.
Hope this helped!
