Question

IF the points A(6,1), B(8,2), C(9,4) and D(p,3) are the vertices of a parallelogram taken in order. Find the value of p.



Is this answer right

AB=CD

AB2=CD2

(6-8)+(1-2)=(9-P)+(4-3)

4+1=81-18+P2+1

P2 -18p+77=0

p2-11p-7p+77=0

p(p-11)-7(p-11)=0

(p-7) (p-11)=0

p=7,11





well but 11 here is not right

i tried it in graph & only 7 seems to be correct!

can somebody tell me why is 11 not correct (as it is mathematically correct)

Answer 1

find midpoint for AC then sustitue in the midpoint of BD since midpoint for both are same