What is the size of the drawing area?

 From:  ggagnon
4128.1 
I hope I can express my question clearly.
When I use Ctrl-P, an image of the drawing area (2560x2048 pixels) is transfered to the clipboard.
I then paste the image in Irfanview and print it.
I can print with a scale 1:1 but to do so I need to know the size of the image in inches when Ctrl-P was depressed.
Without having to resort to measuring it, is there a way to know precisely what the size of the image is in inches?
Thanks,
Gaston