Answer
$1.5$ radians
Work Step by Step
The formula to be used here is $\theta=\frac{s}{r}$ where $s$=arclength, $r$=radius and $\theta$= central angle in radians.
Substituting the values of $r=300$ and $s=450$ in the formula:
$\theta=\frac{s}{r}=\frac{450}{300}=\frac{3}{2}=1.5$ radians
