The Picture and Sound electronics store has hired Pete to work in the warehouse. He uses a pulley with a hand crank to lift heavy boxes. There is a proportional relationship between the number of times Pete turns the crank to lift a box, x, and the height the box has been lifted (in feet), y. x (times Pete turns the crank) y (feet) 4 4 7 7 10 10 18 18 What is the constant of proportionality? Write your answer as a whole number or decimal.