Q9 of 50 Page 220

Three consecutive vertices of a parallelogram ABCD are A (6, – 2, 4), B (2, 4, – 8), C (–2, 2, 4). Find the coordinates of the fourth vertex.

Given; Three consecutive vertices of a parallelogram ABCD are A (6, – 2, 4), B (2, 4, – 8), C (–2, 2, 4).

Let the forth vertex be D(x,y,z).


Midpoint of diagonal AC


Midpoint of diagonal BD





∴ D (2, −4, 16) is the forth vertex.


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