Question

The points (3, -4) and (-6, 2) are the extremities of a diagonal of a parallelogram. If the third vertex is (-1, -3). Find the coordinates of the fourth vertex.

Answer 1

 Let A(3, -4) and C(-6, 2) be the extremities of diagonal AC and B(-1,-3), D(x,y) the extremities of diagonal BD.

Since the diagonals of a parallelogram bisect each other.

Therefore, Coordinates of mid-point of AC = Coordinates of mid point of BD.

Hence, fourth vertex of parallelogram is (-2,1)