resize when pasting

[gus]

Hi guys

so i need to resize a the piece of a image i need, so i measure the image (20,5 x 16,72 Cm)  and create a new file with that size so i can paste and resize later, i proceed and the image end with (4,7 x 6 Cm) which is what i need it.
Now i try to paste my new resize image to the other file and the boody thing now measure 13,58 Cm.
So any idea why the image resize when pasting ?

[Ofnuts]

Likely because the print definitions of the images don't match (see Image>Print size). What Gimp cuts and pastes are pixels.