The problem asks for the constant of proportionality for the number of miles to the number of hours. To calculate this, we use the formula:

$\text{Constant of proportionality} = \frac{\text{Number of miles}}{\text{Number of hours}}$

From the table:

• In the first row: $\frac{12 \, \text{miles}}{4 \, \text{hours}} = 3$
• In the second row: $\frac{6 \, \text{miles}}{2 \, \text{hours}} = 3$

Thus, the constant of proportionality is 3. This means Juan is biking at a speed of 3 miles per hour.

Would you like more details or have any questions?

Here are 5 related questions for further practice:

1. If Juan biked 18 miles in 6 hours, what would the constant of proportionality be?
2. What is the meaning of the constant of proportionality in this context?
3. How can you use the constant of proportionality to predict the number of miles Juan would bike in 5 hours?
4. If Juan increases his biking speed, how would that affect the constant of proportionality?
5. How would you represent the relationship between miles and hours graphically?

Tip: The constant of proportionality represents a rate of change, which in this case is Juan's biking speed.