Final answer:
The constant of proportionality in the equation 0.5x = y is 0.5, which means for every 1 unit increase in x, y increases by 0.5 units. The correct answer is option a) 0.5.
Step-by-step explanation:
In this equation, the variables x and y are directly proportional, which means that as x changes, y changes at a constant rate. This constant rate is represented by the coefficient of x in the equation, which is 0.5. Therefore, for every 1 unit increase in x, y increases by 0.5 units. The coefficient of x in the equation, which is 0.5, represents this constant rate of change. Specifically, for every 1-unit increase in x, y increases by 0.5 units. This constant of proportionality is crucial in understanding how the two variables are connected. In the context of the provided options, option a), which states that the constant of proportionality is 0.5, correctly corresponds to the coefficient in the equation.