calc
posted by Anonymous .
The points P(2, 1), Q(6, 4) and R(4,3) are three verticies of parallelogram PQRS .
Find the coordinate S.

An easy way to do this would be to graph the points. There are actually two answers: one for the case in which Q and R are at opposite corners, and another for the case in which QR is a side of the parallelogram. I assume they want the latter. In that case, S is (8,0). Just make the changes in x and y when going from R to S the same as the changes going from Q to P.