5. Find the coordinates

The points \(A(-1, 8)\), \(B(-9, -5)\) and \(C(7, 8)\) are the vertices of an isosceles right-angled triangle where the right angle is at \(B\). Find the coordinates of \(D\) so that \(ABCD\) is a square.

 

The coordinates of \(D\) \(=\) $\left(i,i\right)$