Question

ABCD is a parallelogram with vertices A (l, yI), B (x2 , y2) and C (x3, y3). Find the coordinates of the fourth vertex D in terms of x1, x2 , x3, yl , y2 and y3.

Answer 1

use the property that the diagonals of a parallelogram each other so (x1+x3)/2 =(x coordinate of D + x2)/2 . similarly for other values .