lenght of the side content

Hi,

I have about 6 menus in my Website, so I have 6 different Sites.

But when I click on the different Menus and the sites opens, they are not equal on the bottom / end of the site, because one site has a lot of text and another site has only a little text.

That looks ugly. How can I handle this, is there an option for such cases? Or do I have to modify a php or css file?

Thank you.