6. If (1, 2), (4, y), (x, 6) and (3, 5) are the vertices of a parallelogram taken in order, find x and y.

Answers (1)
D Divya Prakash Singh

Let the given points A(1,2),\ B(4,y),\ C(x,6),\ D(3,5).

Since the diagonals of a parallelogram bisect each other. Intersection point O of diagonal AC and BD also divides these diagonals.

Therefore, O is the mid-point of AC and BD.

The coordinates of the point O when it is mid-point of AC.

\left ( \frac{1+x}{2}, \frac{2+6}{2} \right ) \Rightarrow \left ( \frac{x+1}{2}, 4 \right )

The coordinates of the point O when it is mid-point of BD.

\left ( \frac{4+3}{2}, \frac{5+y}{2} \right ) \Rightarrow \left ( \frac{7}{2}, \frac{5+y}{2} \right )

Since both coordinates are of same point O.

Therefore,

 \frac{x+1}{2} =\frac{7}{2}  and  4 = \frac{5+y}{2}

Or,

x = 6\ and\ y = 3

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