To determine the constant of proportionality \( k \) from the graph, you need to have specific values for \( x \) (the independent variable) and \( y \) (the dependent variable). The constant of proportionality \( k \) can be calculated using the formula:
\[ k = \frac{y}{x} \]
Please provide specific points from the graph or any values of \( x \) and \( y \) you want to use in the calculation. Once you have the values, simply divide \( y \) by \( x \) to find \( k \).