To complete the equation \(y = x\) with its constant of proportionality for the ice cream custard cost, you need to identify the constant of proportionality (k) that relates the cost (y) to the weight (x) in ounces.
In the context of direct proportionality, the equation can be expressed as:
\[ y = kx \]
In this case, you would need the specific cost of the custard per ounce to determine the constant \(k\). If you can provide that information (for example, if the cost of 1 ounce of ice cream is $2, then \(k = 2\)), I can help you complete the equation accordingly.
If, for example, the cost is $2 per ounce, then:
\[ y = 2x \]
Please provide the cost per ounce or any additional information to complete the equation accurately.