Q20 of 149 Page 14

The three vertices of a parallelogram are (3, 4), (3, 8) and (9, 8). Find the fourth vertex.

Consider A(3, 4), B (3, 8) and C(9, 8).


Let the coordinates of fourth vertex are D (x, y)


In a parallelogram diagonals bisect each other


Coordinate of mid point of AC =



Therefore coordinates of mid point of AC are (6, 6)


Coordinate of mid point of BD =



Coordinates of point D are






Therefore coordinates of fourth vertex D are (9, 4)


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