title: NSArray - getting the closest object to origin
body: <p>using Objective-C for iPhone, I'm attempting to gather the closest object to my origin.<br>
  All my objects are in an NSMutableArray and have CGPoint property of their current location.   </p>
  
  <p>Using simple trig I can find the magnitudes of all my objects with ease, but <em>Im trying to find the <strong>'closest'</strong> object to my origin</em>. Does anyone have any idea how to do this?   </p>