Locate the points A (1, 2), B (4, 2) and C (1, 4) on a graph sheet taking suitable axes. Write the coordinates of the fourth point D to complete the rectangle ABCD.

The points in the graph are

A = (1, 2)

B = (4, 2)

C = (1, 4)

The incomplete rectangle on the graph will look like

The completed rectangle ABCD on the graph is

∴ The coordinates of point D, to complete the rectangle ABCD are D (4, 4).