Inconsistent Line position between filles

[toymaker1]

Hello

I have attached a screen shot of two artboards. Each artboard has a horizontal line at 190mm from the top (position Y). When I place the two artboards next to each other, both at 33.3%, the position of the lines is visibly different. I would expect them both to look exactly the same. Can anyoone explain why the lines appear to be at a different position on each page, even though they were placed at exactly the same position?

[Met1 · Accepted solution]

Your left hand doc doesn't start at 0.

[toymaker1]

Hi Met1
Thanks for your response. Your advice has resolved my issue. - I had no
idea that there were two sorts of rulers; Rulers, and Artboard Rulers.
Thanks again.