Find the relation if `z_1, z_2, z_3, z_4` are the affixes of the vertices of a parallelogram taken in order.

Explanation

As the diagonal of a parallelogram bisect each other, therefore, comnplex number of the mid-point of AC is same the complex number of the mid point of BD.

`therefore (z_(1) + z_(3))/(2) = (z_(2) + z_(4))/(2)`
or `z_(1) + z_(3) = z_(2) + z_(4)`