Final answer:
The relationship between the total cost of concert tickets and the number sold is direct proportionality, with the equation being c = 53m, where c is the total cost and m is the number of tickets.
Step-by-step explanation:
The question deals with the concept of direct proportionality in a real-world context. Since the total cost of concert tickets, c, is directly proportional to the number of concert tickets, m, sold, and Tiana spent $212 for four concert tickets, we can find the cost per ticket and then create a formula representing this relationship. The cost per ticket is $212 divided by 4, which equals $53 per ticket. Therefore, the equation representing the direct proportionality is c = 53m, where c is the total cost and m is the number of tickets.