You need a Ruler and there is no in your slide. Follow these steps:
- Go to the ribbon to the View tab.
- Tick the Ruler check box.
- Now your Ruler should be visible. It could happen that a vertical ruler is still missing. In this case go to the ribbon and click File.
- Go to Options.
- In Advanced menu tick Show vertical ruler check box.
Now for sure bot vertical and horizontal rulers are visible.