To find the equation representing a proportional relationship in a graph for $y$ in terms of $x$, let's outline the general process:

1. Proportional Relationship: In a proportional relationship, the equation takes the form: $y = kx$ where $k$ is the constant of proportionality.

2. Determine $k$: If given a point on the graph (for example, $(x, y) = (a, b)$), we can substitute to solve for $k$: $k = \frac{y}{x}$

3. Form the Equation: Once $k$ is found, substitute back to write the equation as $y = kx$.

If you can provide specific points from the graph or an image, I can guide you through finding the exact equation.

Would you like more detailed steps?

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1. What is a proportional relationship in mathematics?
2. How do you determine the constant $k$ in proportional relationships?
3. How can you identify a proportional relationship from a graph?
4. What happens to the graph if $k$ is negative?
5. How does a proportional equation differ from a linear equation?

Tip: For proportional graphs, the line always passes through the origin, as $y = kx$ means $y = 0$ when $x = 0$.