The equation that represents the proportional relationship on the graph is; y = (1/3)·x
What is a proportional relationship; A proportional relationship is a relationship is one in which there is a direct variation between the input, and output variable, such that the output variable, y, is a multiple of the input variable, x, and a constant; y = k·x
Where k is the constant of proportionality
The points on the graph are; (9, 3), (6, 2), (3, 1), and (0, 0)
The proportional relationship, indicated by the point (0, 0), on the straight line graph, can be represented by the above equation for a proportional relationship, y = k·x, as follows;
The constant of proportionality, k = y/x
The point (9, 3) on the graph indicates that we get;
y/x = 3/9
Similarly, y/x = 2/3
3/9 = 2/6
2/6 = 1/3
3/9 = 1/3
k = 3/9
Therefore, k = 1/3
The equation that represents the proportional relationship in the graph therefore is; y = (1/3)·x