On the complex plane, the number is mapped onto the point with coordinates
.
In other words, the x coordinate is the real part of the number, while the y coordinate is the complex part of the number.
Viceversa, if you start from a point , you can identify the number
.
So, the endpoints of the diagonal are the points and
. These are points A and C in the attached figure.
This means that points B and D have coordinates
So, the correspondant complex numbers are
