Stack Overflow Example: 3 side-by-side DIV elements with matching heights.

Align 3 divs on a single row, with matching heights.

HTML

<div id="wrapper">
  <div id="row">
    <div id="first">first</div>
    <div id="second">second<br><br></div>
    <div id="third">third</div>
  </div>
</div>

CSS

#wrapper {
    display:table;
    width:700px;
}
#row {
    display:table-row;
}
#first {
    display:table-cell;
    background-color:red;
    width:200px;
}
#second {
    display:table-cell;
    background-color:blue;
    width:300px;
}
#third {
    display:table-cell;
    background-color:#bada55;
    width:200px;
}