Then choose Widescreen (16:9) to make your presentation widescreen. Now click Slide Size to open the popup menu. Change a Presentation to Widescreen in Microsoft PowerPoint for Mac In order to change the aspect ratio of your presentation, open PowerPoint editor and choose the Themes menu. Below we will see a useful tip for Mac users of PowerPoint that will help you to create widescreen presentations or convert your existing presentations to widescreen format. In PowerPoint for Mac you can also change the default aspect ratio from 4:3 to 16:9 to make modern widescreen presentations.
