Solution:
the arc lenght s, of a circle of radius r, with central angle θ, is given by the following equation:
[tex]s\text{ = }r\theta[/tex]solving for r, we get the following equation:
[tex]r\text{ = }\frac{s}{\theta}[/tex]now, replacing in the previous equation the data given in the problem we get:
[tex]r\text{ = }\frac{s}{\theta}\text{ = }\frac{35\pi}{5\pi\text{ / 6}}\text{ = }\frac{(35\text{ }\pi)\text{ 6 }}{5\pi}\text{ = 42 }[/tex]so that, we can conclude that the correct answer is:
[tex]42\text{ cm}[/tex]