You’re not limited to one slide size within a presentation.
Here’s how to adjust the dimensions of an individual slide:
- Within the presentation you’d like to edit, find the slide you want to resize in the Table of Contents panel.
- Click on the gear that appears when you hover over the slide.
- Click Edit Properties from the dropdown menu.
- In the Slide Properties window that appears, scroll down to Slide Size.
- Choose a size, or create your own custom size.
- Click Save.