Align Selected Objects on the Slide
In most cases you will find it easiest to first align the objects where you want them to end up on the slide. In the example shown, the centers of each object have been aligned, using the Align Middle option. This makes the center of each each object aligned with the others. However, they may still be unevenly spaced between each other. This can be corrected using the Distribute options.
Distribute Selected Objects, Relative to Each Other
From the Drawing toolbar, choose Draw > Align or Distribute > Distribute Horizontally (or Vertically)
This will distribute the total space between all the objects selected, from the outside edges of the two outermost objects.
Note in the example shown that the objects are still too close together and are not truly in the middle of the slide. This will be addressed in the next step.
