Question

a(0, 1), b(4, 4), c(12, 4), d(8, 1)

Explanation:

Answer:

Quadrilateral \(ABCD\) is a parallelogram, as \(AB \parallel DC\) and \(AB = DC\), \(AD \parallel BC\) and \(AD = BC\).
The completed graph has vertices \(A(0,1)\), \(B(4,4)\), \(C(12,4)\), \(D(8,1)\) connected in order.