How to Hide Ribbon in Sharepoint 2010

It may be your Boss ask to hide sharepoint Ribbon and you dont have any idea about that :(
So you are in big trouble. But no need to worry here is the solution.
First what is Ribbon in sharepoint?
The place where we find option to Site Setting is Called Ribbon and that is enclosed  in one Div called Ribbon.

This is the Ribbon in SharePoint.
Now we need to hide this, it comes under one div so if we hide that div it will be hidden automatically.
Then question is how to find that div.
Answer is that in every Sharepoint master page it comes at same div that is "s4-ribbonrow".

So you need to hide this div only, here is solutions.

 <div id=”s4-ribbonrow” class=”s4-pr s4-ribbonrowhidetitle”>
    <!--- this is the div where ribbone content is present...-->
 </div>
  <style type="text/css">
     <!-- this is style which we use for hide the content it will go to master page or ur css file --->
     #s4-ribbonrow{ display:none; }
   </style>
If you face any problem regarding of this post let me know i will try to solve that