This post by Ashley Chin-Mark explains some of the many correlations between math and ballet. She explains how in ballet the dancers need to be aware of both negative and positive space, as well as study symmetrical movements and shapes. Dancers also need to calculate as well as predict how to best use the stage to perform their routines. She also talks about different alignments of body parts especially in the 8 corners method and how dancers rotate their bodies, in order to achieve symmetrical lines.
This post is helpful to me because it has a lot of detailed information with really specific examples of when and how math is used in ballet. Also, it showed me that dancers need to make a lot of calculations as to how to best use the stage to perform their routines, as well as avoid from accidentally bumping into/kicking each other.