This website talks about the mathematical reasoning behind dance, but more specifically ballet. One example the website gave is, symmetry, it´s very important that one side of the body matches the other side. Being symmetric helps a dancer with balance. Symmetry usually contributes to the formations of the dancers in a dance. Another example is rhythm, dancers must be able to count the number of counts in a step as well as the beats in music. The most counts in a full set 8.
This site was helpful because not only did it explain the different connections between math and ballet, it also explained why they believed math was in ballet. This website not only explained the connections between math and ballet but other dances as well.