The points P1,3,4,Q−1,6,10,R−7,4,7 and Sforms Rhombus thenS=

The points  P1,3,4,Q−1,6,10,R−7,4,7forms Rhombus in the order. The fourth vertex isS=P+R−QHence,S=1−7+1,3+4−6,4+7−10=−5,1,1Therefore, the fourth vertex is−5,1,1