The vertices a (- 1,2), B (2,1), C (4,3) of the parallelogram ABCD are known The vertices a (- 1,2), B (2,1), C (4,3) of the parallelogram ABCD are known (1) Find the coordinates of the fourth vertex D (2) Coordinates of the intersection of diagonal lines AC and BD fast

The vertices a (- 1,2), B (2,1), C (4,3) of the parallelogram ABCD are known The vertices a (- 1,2), B (2,1), C (4,3) of the parallelogram ABCD are known (1) Find the coordinates of the fourth vertex D (2) Coordinates of the intersection of diagonal lines AC and BD fast

1. Coordinates of D (1,4)
2. Coordinates of intersection (3 / 2,5 / 2)
1. Vector problem. The vectors from a to B and D to C are equal, that is, XB XA = XC XD, Yb Ya = YC YD
2. The intersection of parallelogram diagonal AC and BD is the midpoint of the diagonal. The X coordinate of the midpoint is the midpoint of the X coordinate of AC, that is, 3 / 2,
The Y coordinate of the midpoint is the midpoint of the Y coordinate of AC, which is 5 / 2
The X and Y coordinates can be calculated separately