Creating same size boxes.

How do I make boxes the same size? Or at least set each to a minimum size?

For instance, on my home page, I have three CTA boxes side by side. Of course, then the browser is resized, they change size. But since they text is not the exact same length, they are often each a different size.

I have another page (not published yet) where I’d like to accomplish the same thing, but with text boxes.

Is there a way to do this?

Website in question is http://www.webologist.co (home page, scroll down)