1. The problem asks to find the unit rate and the constant of proportionality for calories burned per minute based on the given data points. 2. The data points given are (2, 20), (4, 40), (6, 60), and (8, 80), where the first coordinate is time in minutes and the second is calories burned. 3. The formula for unit rate or constant of proportionality in a proportional relationship is: $$\text{unit rate} = \frac{\text{calories burned}}{\text{time in minutes}}$$ 4. Calculate the unit rate using any point, for example (2, 20): $$\frac{20}{2} = 10$$ 5. Check with another point (4, 40): $$\frac{40}{4} = 10$$ 6. Since the ratio is constant for all points, the constant of proportionality is 10 calories per minute. 7. This means Coach Rowley burns 10 calories every minute he rides the bike. Final answer: The unit rate and constant of proportionality are both 10 calories per minute.