or
During the summer, Charlotte works on her uncle's dairy farm. One of Charlotte's many chores is to load bales of hay onto a wagon and haul them from the field into the barn.
There is a proportional relationship between the number of wagon loads, x, and the number of bales of hay Charlotte can haul, y.
x (wagon loads) y (bales)
1 3
2 6
4 12
5 15
What is the constant of proportionality? Write your answer as a whole number or decimal.