Final answer:
Symmetrical balance is the hair design created when the two halves of a hairstyle form a mirror image of each other.
Step-by-step explanation:
The hair design that is created when the two halves of a hairstyle form a mirror image of each other is symmetrical balance. Symmetrical balance is characterized by an exact or nearly exact compositional design on either side of the horizontal or vertical axis. This creates a visually stable and balanced look.