Answer
$0.6~rad $ or $34^{\circ}$.
Work Step by Step
Given the wheel diameter of $1m=100cm $, its circumference should be $100\pi cm $, which is the distance a complete turn ($2\pi $) of the wheel will move.
Hence, a 30cm travel corresponds to an angle of $\frac{30}{100\pi}\times 2\pi=0.6 rad $
equivalent to about $34^{\circ}$.
