Need to rotate your PowerPoint slides? By default, PowerPoint 2010 slide layouts are presented in landscape page orientation, or you can rotate your slide layouts to portrait page orientation.
Portrait page orientation
Landscape page orientation
To rotate all slides in a presentation to portrait orientation, do the following:
On the Design tab, in the Page Setup group, click Slide Orientation, and then click Portrait .
Note: To display both portrait and landscape slides in what appears to be the same presentation, see the blog post A good old-fashioned workaround on how to rotate slides: Using portrait and landscape orientation in the same presentation..