I need help with these word problems

1)
$\omega = 7rad/s\\ r=15cm\\ v_{tan}=\omega r\\ v_{tan}= 7rad/s*(15cm)=105cm/s*(60s/1min)=6300cm/min$
3)
$\Delta \theta=\frac{3\pi}{4}rads\\ t=2s\\ \omega = \frac{\Delta \theta}{t}=\frac{\frac{3\pi}{4}rads}{2s}=\frac{3\pi}{8}rad/s$