9514 1404 393
Answer:
A. (3, 2)
Step-by-step explanation:
The midpoints of the diagonals are the same point, so you have ...
X = (A +C)/2 = (B +D)/2
A +C = B +D . . . . . . . multiply by 2
A +C -B = D . . . . . . . subtract B
The coordinates of D are ...
D = (3, 6) +(6, 3) -(6, 7) = (3+6-6, 6+3-7)
D = (3, 2)
