title: Fluid Layout - how to get initial percentage value
body: <p>When creating a fluid layout as a base for a responsive design - how do you reach the inital percentage value for the main container.  For example a fixed layout might start with the container of 930px wide with a 15px padding on either side.  </p>
  
  <p>I need to know how to get that inital 930 value expressed as a percentage.</p>