Answer: 7.25 dollars per hour.
Explanation:
The constant of proportionality is the ratio of two variables , y (dependent variable) to x (independent variable).
Given: Savannah was paid $87 for 12 hours of babysitting and $65.25 for 9 hours.
Here , Number of hours is independent variable and the amount she gets for babysitting with respect to number of hours is dependent variable.
Therefore,
dollars per hour
Also,
dollars per hour
Hence, the constant of proportionality describes the given relationship = 7.25 dollars per hour.