Answer
Radius of the circle = 18 m
Work Step by Step
$$r \theta = s$$ $$r = \frac{s}{\theta}$$
r = radius
s = length of arc = $13 \pi$ m
$\theta = $ angle = 130$^o$
In order to use this formula, the angle must be converted to radians, which is done by multiplying the angle in degrees by $\frac{\pi}{180}$.
$$\theta = 130^o \times \frac{\pi}{180} = \frac{13\pi}{18} $$
$$r = \frac{13 \pi \space m}{ \frac{13\pi}{18}} = 18 \space m$$
