The parametric equations of the line are given by $x= –2+ \frac{r}{\sqrt{10}}$ and $y= 1+ \frac{3r}{\sqrt{10}}$ then for the line

The parametric equations of the line are given by $x= –2+ \frac{r}{\sqrt{10}}\Rightarrow \frac{r}{\sqrt{10}}=x+2\Rightarrow \frac{3r}{\sqrt{10}}=3x+6$ and $y= 1+ \frac{3r}{\sqrt{10}}\Rightarrow y- 1= \frac{3r}{\sqrt{10}}$

$$\begin{gathered} \Rightarrow 3x+6=y-1 \\ \Rightarrow 3x-y+7=0 \\ \Rightarrow slpoe =3 \\ \Rightarrow \tan \theta =3 \\ \Rightarrow \theta ={\tan }^{-1}3 \end{gathered}$$