Answer
$0.6 \text{ radians}$
Work Step by Step
$\because s = r \theta$
where
$s$: Length of the arc of the circle
$r$: Radius of the circle
$\theta$: Central angle that subtends the arc (in radians)
Use the formula above to obtain:
$s=r\theta\\
\dfrac{s}{r}=\theta\\
\theta=\dfrac{s}{r}\\$
$\theta = \dfrac{3}{5} = \boxed{0.6 \text{ radians}}$
