You have a few options:
You may use display: table
and assign table 'rows' and 'columns' on div tags.
Or
You may use float: left
which will line everything like a table and be more responsive.
Or
You may use display: inline-block
which will behave a lot like the floats except you get a little bit more control on box height.
There is no correct answer here but my preference is with inline-block
since browser support tends to be superior than floats while keeping everything responsive.