Final answer:
The constant of proportionality in this situation is the slope of the line. An ordered pair on this graph could be (5,15) which represents 5 magnets sold for $15.
Step-by-step explanation:
The constant of proportionality in this situation is the slope of the line. In the graph, the slope represents the cost per magnet. It tells us how much the cost increases or decreases for each magnet sold. For example, if the slope is 2, it means that for every additional magnet sold, the cost increases by $2.
An ordered pair on this graph could be (5, 15). This represents that 5 magnets were sold for $15. The x-coordinate (5) represents the number of magnets sold, and the y-coordinate (15) represents the cost.