Determine the constant of proportionality (unit rate) per order of popcorn for each company.

Movie Company:
Movie mania
Fantastic Flicks
Perfect picture
The big screen

Constant of proportionality:

Since the constant of proportionality (unit rate) per order of popcorn varies for each company, it is not possible to determine it without additional information. The constant of proportionality would depend on various factors, such as the size of the order, the type of popcorn, and any discounts or promotions offered by each company.