Here are the positions of points `A`, `B` and `C`:

12345-1-2-3-4-5123-1-2-3-4-5xyABCOpen image in a new page

Since the opposite sides of a rectangle are equal and parallel, we can see that:

The y co-ordinate of D must be `1`

The x co-ordinate of D must be `-3`

We conclude the co-ordinates of D are `(-3, 1)`.

Here's our completed rectangle:

12345-1-2-3-4-5123-1-2-3-4-5xyABCDOpen image in a new page

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