FitToPage Property

Microsoft PowerPoint Visual Basic

Determines whether the slides will be scaled to fill the page they're printed on. Read/write MsoTriState.

MsoTriState can be one of these MsoTriState constants.
msoCTrue
msoFalse Default. The slides will have the dimensions specified in the Page Setup dialog box, whether or not those dimensions match the page they're printed on.
msoTriStateMixed
msoTriStateToggle
msoTrue The specified slides will be scaled to fill the page they're printed on, regardless of the values in the Height and Width boxes in the Page Setup dialog box (File menu)

Example

This example prints the active presentation and scales each slide to fit the printed page.

With ActivePresentation
    .PrintOptions.FitToPage = msoTrue
    .PrintOut
End With