Make the 3 content areas in front page the same size on different browsers

Hi all dear Melos users,

I’ve been playing with the images and text on the front page to make the 3 content areas the same size. I made the three images exactly of the same size each and modified the text length in order to adjust the size.

I managed to get it done working on Google Chrome but, when tested the site using Firefox or Internet Explorer the three areas look with different sizes!

Any ideas of how to make these three content areas the same size regardless the browser you use?
Thank you in advance!