since the diameter is 66 cm, then its radius is half that or 33 cm.
[tex]\textit{arc's length}\\\\ s=r\theta ~~ \begin{cases} r=radius\\ \theta =\stackrel{radians}{angle}\\[-0.5em] \hrulefill\\ r=33\\ \underset{complete~turn}{\theta =2\pi ~\hfill } \end{cases}\implies s=(33)(2\pi )\implies s=66\pi \implies s\approx 207.34~cm[/tex]
