The diameter of the circle is given as
[tex]\begin{gathered} \text{diameter}=2\times radius\text{ of the circle} \\ d=2r \end{gathered}[/tex]
The given radius is
[tex]=9\operatorname{cm}[/tex]
Therefore, the diameter will be
[tex]\begin{gathered} \text{diameter =2}\times9\operatorname{cm} \\ \text{diameter =18cm} \end{gathered}[/tex]
Hence,
The diameter of the circle =18 centimeters
