Tip: (Acrobat only, not Adobe Reader) You can set up a PDF to default to specific scaling or print options. Choose File > Properties, and click the Advanced tab. Select options for the Print Dialog Presets. The Default option in the Page Scaling pop-up menu is Shrink To Printable Area. Save the file to apply the new defaults. For more information, see Print Dialog Presets in Acrobat Help.
Not available in Adobe Reader 9: Scale using the preset scale options in Adobe Reader 9 or earlier.
You can magnify or reduce a PDF by an exact percentage.