Here are a couple things to try:
1. In Mozilla, in the menu, click on edit, preferences, appearance, fonts. Then look to the display resolution, and click on the checkmark. That should open up a menu. Click 'other', then measure that line and type in the measurement (check whether it's inches or milli.) If that doesn't fix the fonts to the size you want, play around with the number there a bit, making it higher or lower. Should help in at least Mozilla, if not the rest.
2. Fonts can also be controlled overall by clicking the redhat menu at the bottom of the screen (in the gnome settings, at least,) then preferences, and then font. Also check out that there is a second screen available, not just the opening one.
Hope that helps.