Question

 If P(1, 2), Q(4, 6), R(5, 7) and S(a, b) are the vertices of a parallelogram PQRS, then ​

Answer 1

Explanation:

PQRS is a parallelogram if and only if the mid point of the diagonals PR is same as that of the mid point of Q, S. That is, if and only if

$\frac{1 + 5}{2} = \frac{4 + a}{2}$

$and$

$\frac{2 + 7}{2} = \frac{6 + b}{2}$

$= > \: a = 2 \: \: \: and \: \: \: b = 3$