Print: Scale (X, Y) values (Eureka !)

The LR states for ScaleX (but same for Scale Y) ScaleX :

Graphics.ScaleX Property (As Double ) aGraphics.ScaleX = newDoubleValue or DoubleValue = aGraphics.ScaleX The scale factor used when converting user space coordinates to backing store coordinates. These can be modified at runtime and must be greater than zero.

How can I understand these two properties are for the Print process ?
(You know the % value that appears in PageSetup !)

Worst, with CMY, the value is explained as:

The value of Cyan in the color (0-1).

This is the same process: if you enters 70 (“Print at for 70%”), Graphics.ScaleX and Graphics.ScaleY are filed wit 0.7.

Of course, this simple Eureka is for the people (like me) who do not understand that by themselves. (or know).