The equation to describe the number of tights Ms. Andrea could order is tights = dancers which is t = d.
Ms. Andrea orders the same number of pairs of tights as there are dancers in the class.
This implies there is a direct proportional relationship between the number of dancers and the number of tights ordered.
The equation T = D expresses this proportional relationship, where T and D are directly proportional to each other.
This means that as the number of dancers increases, the number of tights ordered also increases proportionally.
Therefore, T = D accurately represents the number of tights Ms. Andrea could order based on the number of dancers in the eight-year-old class.