In the Advanced Properties window…
Alternatively select a preset page size and skip the Postscript Custom Page
size step.
Finally, in the Postscript Custom Page Size window…
Then select OK in all windows to print.
Note: The maximum page size in Powerpoint is 60”x60”. So, if you would
like a longer poster, you’re out of luck—use Illustrator instead.
1) Select Postscript
Custom Page Size
2) Select Edit
Custom Page Size
1) Enter Shortest
Dimension
2) Enter Longest
Dimension
3) Select Short
Edge First