In each of the following, the co-ordinates of the three vertices of a rectangle ABCD are
given. By plotting the given points; find, in each case, the co-ordinates of the fourth vertex:
(i) A (2, 0), B (8, 0) and C (8, 4).
(ii) A (4, 2), B (-2, 2) and D (4, -2).
(iii) A (-4, -6), C (6, 0) and D(-4, 0).
(iv) B (10, 4), C (0, 4) and D(0, -2).