PresentationPageSetup
Contains information about the page setup for slides, notes pages, handouts, and outlines in a presentation.
Using the PageSetup Object
Use the PageSetup property to return the PageSetup object. The following example sets all slides in the active presentation to be 11 inches wide and 8.5 inches high and sets the slide numbering for the presentation to start at 17.
With ActivePresentation.PageSetup
.SlideWidth = 11 * 72
.SlideHeight = 8.5 * 72
.FirstSlideNumber = 17
End With