#### Answer

$25.8$ cm

#### 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: Substituting the values of the question into the formula,
$s=(12.3)(\frac{2\pi}{3})$
Step 3: $s=\frac{41\pi}{5}= 25.8$ cm