since the diameter of the circle is 6 inches, then the radius will be half that, or 3 inches,
[tex]\bf \textit{arc's length}\\\\
s=\cfrac{r\pi \theta }{180} \quad
\begin{cases}
r=radius\\
\theta =angle~in\\
\qquad degrees\\
------\\
r=3\\
\theta =70
\end{cases}\implies s=\cfrac{3\cdot \pi \cdot 70}{180}\implies s=\cfrac{7\pi }{6}[/tex]
