TEKS 8(1)(D), 8(4)(B), 8(5)(A)
Example Graphing Proportional Relationships
A video game store has a frequent shopper program. You earn 4 points for every video game you buy. Draw a graph to model this situation.
You need 48 points for a free game. How many video games do you need to buy to have enough points for a free game?
For every game you buy, you earn 4 points. Since you can only buy entire games, it only makes sense to plot points with x-coordinates that are whole numbers. For each point on the graph, the y-coordinate should be four times the x-coordinate.
Since you need 48 points for a free game, look for a point on the graph until you reach a y-coordinate of 48.
You need to buy 12 games to have enough points for a free game.