Angles Subtended by the Arcs or Chords

The length of arc $\stackrel{⏜}{PQ}$ is three times the length of arc $\stackrel{⏜}{QR}$ in a circle with centre $O$. Measure of $\angle POQ$is $105°$. If the measure of $\angle QOR$ is $k°$ then find the value of $k$.

Arc $\stackrel{⏜}{AB}$ of $5 \mathrm{cm}$ length in a circle with centre $O$ subtends $25°$ at the centre. Arc $\stackrel{⏜}{CD}$ subtends $100°$ at the centre $O$. If the length of arc $\stackrel{⏜}{CD}$ is $k \mathrm{cm}$ then find $k$.