Answer:
Balance is a design principle; symmetry is a tool often used to achieve balance.
Step-by-step explanation:
Balance is a visual effect used to make a design appear as if it is equally weighted on either side of its vertical center.
The use of mirror imaging and repetition is known as symmetry.
Balance can be achieved symmetrically or asymmetrically. The attached picture is an example of asymmetrical balance (with many small things balancing out one larger object). For the image to be symmetrically balanced, the four small circles would have to be replaced by an object the same size as the square.