Taking it further

Three of the four lines enclosing a square are given by the following equations.

  1. \(\mathbf{r}=\begin{pmatrix}0\\2\end{pmatrix} + a\begin{pmatrix}1\\3\end{pmatrix}\)
  1. \(\mathbf{r}=\begin{pmatrix}5\\1\end{pmatrix} + b\begin{pmatrix}-3\\1\end{pmatrix}\)
  1. \(\mathbf{r}=\begin{pmatrix}3\\3\end{pmatrix} + c\begin{pmatrix}3\\-1\end{pmatrix}\)

Find the fourth equation and the area of the square.