To find the constant of proportionality, $\frac{y}{x}$, we need to choose a point on the graph and calculate the ratio of $y$ to $x$.

From the graph, one clear point is $(1, 50)$. At this point:

$\frac{y}{x} = \frac{50}{1} = 50.$

Thus, the constant of proportionality is 50.

Would you like further details or help solving similar problems?

Here are 5 follow-up questions related to this topic:

1. What does the constant of proportionality represent in a real-world context?
2. How can you verify if a relationship is proportional by looking at a table of values?
3. What is the equation of a line with a proportional relationship between $y$ and $x$?
4. How do proportional relationships differ from linear relationships that are not proportional?
5. How would the graph change if the constant of proportionality were larger or smaller?

Tip: Always check the origin in proportional graphs—it must pass through $(0, 0)$ for the relationship to be proportional!