Question
If $(x_1, y_1), (x_2, y_2)$ and $(x_3, y_3)$ are the vertices of a triangle whose area is $k$ square units, then $\begin{vmatrix} x_1 & y_1 & 4 \\ x_2 & y_2 & 4 \\ x_3 & y_3 & 4 \end{vmatrix}^2$ is
If $(x_1, y_1), (x_2, y_2)$ and $(x_3, y_3)$ are the vertices of a triangle whose area is $k$ square units, then $\begin{vmatrix} x_1 & y_1 & 4 \\ x_2 & y_2 & 4 \\ x_3 & y_3 & 4 \end{vmatrix}^2$ is