#### Answer

$1$ radians

#### 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, r is the radius and $\theta$ is the central angle of measure in radians.
Step 2: $s=r\theta$
Step 3: $3=(3)(\theta)$
Step 4: $\theta=1$ radians