Symmetrical balance:

A vertical axis is required to achieve a balance with symmetry. Part of the reason is that we have struggled throughout our lives to perfect our balance in order to stand, walk, ride a bike, etc. To do this, we must have exactly the same weight on both sides of our bodies. Our axis of symmetry is vertical and this makes a good model for symmetry in visual information.

Symmetrical balance is also called formal balance because we use a mirror image formula. A mirror image formula is a reflection of an image on its vertical axis . The results of this look formal, organized and orderly. See fig.119

Figure 125. Balance with symmetry and equality.