If A(1, 2), B(4, y), C(x, 6) and D(3, 5) are the vertices of a parallelogram ABCD, then find the values of x and y.
Answer & explanation
Correct answer: option 2
Let A,B,C and D be the points (1,2) (4,y), (x,6) and (3,5) respectively.
Mid point of diagonal AC is ((1+x)/2,(2+6)/2)⇒((x+1)/2,4)
Mid point of diagonal BD is((4+3)/2,(5+y)/2)⇒(7/2,(5+y)/2)
Since the diagonals of a parallelogram bisect each other, the midpoints of AC and BD are the same.
∴(x+1)/2=7/2 and 4=(5+y)/2
⇒x+1=7 and 5+y=8
⇒x=6 and y=3
The correct answer is Option (2) → $x=6, y=3$