Chapter 3 - Radian Measure and the Unit Circle - Section 3.2 Applications of Radian Measure - 3.2 Exercises - Page 110: 13

$25.8$ cm

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