To determine the constant of proportionality, we first need to convert Julian's walking speed into miles per hour.
Given that Julian takes 1/2 hour to walk 2 miles, we can find his speed in miles per hour as follows:
-
Convert 1/2 hour to hours: \[ \text{1/2 hour} = 0.5 \text{ hours} \]
-
Calculate the speed: \[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{2 \text{ miles}}{0.5 \text{ hours}} = 2 \div 0.5 = 4 \text{ miles per hour} \]
Therefore, the constant of proportionality \( \frac{y}{x} \) (where \( y \) is the distance in miles and \( x \) is the time in hours) is: \[ \text{The constant of proportionality is } 4 \text{ miles per hour.} \]