Answer
$55.3$ inches
Work Step by Step
Step 1: The formula to be used here is $s=r\theta$ where $s$ is the length of the arc intercepted on a circle of radius $r$ by a central angle of measure $\theta$ radians.
Step 2: First, we need to convert the angle from degrees to radians,
$210^{\circ}=210(\frac{\pi}{180})=\frac{7\pi}{6}$ radians
Step 3: Substituting the values of the question into the formula,
$s=(15.1)(\frac{7\pi}{6})$
Step 4: Simplifying, $s= \frac{1057\pi}{60}=55.3$ inches
