Why is my document printing in the wrong format?

i have a 4 page document in portrait format but when trying to print it come up in the landscape format. I can’t find anything on my printer about the orientation and it usually just prints like it was written. What can I do to solve this problem?

Supposedly working on a Mac with OSX Sierra and paper size USA ‘Letter’.
There were many topics here about the issue. See this one e.g.
From a comment there:
The issue was discussed as bug tdf#92190 and seems to be fixed in version LibO 6.0 to come soon, and most likely already in V5.4.4 or 5.4.5

a workaround is here .

Make sure the page style isn’t accidentally set to landscape.

Same problem for me.
Recently LibreOffice (ver. 5.0.4) has started changing page orientation from Portrait to Landscape.
I have been unsuccessful in finding a way to correct this. How or where can the Page Setup be changed or corrected?

And this answer is yet another great contribution to help original questioner to solve this! Thanks!