this is my question:
the points A(1,2), B(3,5), C(6,6) and D form a parallelogram. Find the coordinates of the mid point of AC. use your answer to find the coordinates of D.
firstly i have found the mid points of AC which=(7,8)
secondly i don't really know how to use (7,8) to find the D coordinate.
Lastly i would really appreciate some help please, but could you really explain it so i understand!