The direct variation equation given is \( y = 7.5x \), where \( y \) represents the number of minutes Chaquille spends running and \( x \) represents the number of miles he runs.
In this equation, the constant of proportionality is \( 7.5 \). This constant represents the number of minutes it takes Chaquille to run one mile. In this context, it indicates that for every mile he runs, he spends 7.5 minutes running.
To verify the context of this constant:
- Since Chaquille runs 3 miles in 22.5 minutes, we can calculate the time it takes him to run one mile by dividing the total time by the number of miles: \[ \frac{22.5 \text{ minutes}}{3 \text{ miles}} = 7.5 \text{ minutes per mile} \] This confirms that the constant of proportionality \( 7.5 \) accurately reflects the time per mile that Chaquille takes to run.