This graph shows a proportional relationship.

What is the constant of proportionality?

Enter your answer in the box.

Graph of a ray in the first quadrant. The vertical axis is labeled Replanted trees. The horizontal axis is labeled Area in acres. The horizontal axis ranges from 0 to 10 in increments of 1. The vertical axis ranges from 0 to 500 in increments of 50. A line passes through the origin and the points begin ordered pair 3 comma 135 end ordered pair and begin ordered pair 5 comma 225 end ordered pair.