CSS display table
by JM note
HTML
<style>
.row {
width: 100%;
display: table;
}
.box { display: table-cell; }
.box-a { background: red; width: 50px; }
.box-b { background: orange; }
.box-c { background: yellow; width: 50px; }
</style>
<div class="row">
<div class="box box-a">A</div>
<div class="box box-b">B</div>
<div class="box box-c">C</div>
</div>