The price for footballs is displayed in the graph. Derive the equation of the proportional relationship through the origin

To find the equation of the proportional relationship through the origin, we need to determine the ratio of the price to the number of footballs for each data point:

For the data point (1, 9):
9/1 = 9

For the data point (2, 18):
18/2 = 9

For the data point (3, 27):
27/3 = 9

Since the ratio is the same for all data points, we can conclude that the equation of the proportional relationship through the origin is:

y = 9x

Where:
y represents the price of the footballs
x represents the number of footballs