Mini Display Port To VGA Adapter:
Every Mac with a Mini Display Port allows you to connect an external display or projector using an adapter. You can use an external display as your main work space or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees.
Use the Mini Display Port to VGA Adapter to connect your Mac to a standard analog monitor, projector, or LCD that uses a VGA connector or cable. Review the documentation or check with the manufacturer of your monitor to make sure you're choosing the right adapter.