An ice cream shop serves chocolate milkshakes that are made with ice cream and milk. There is a proportional relationship between the number of scoops of ice cream and the amount of milk needed to make them. For every 1 scoop of ice cream, one half cup of milk is needed, and for every 7 scoops of ice cream, three and one half cups of milk are needed.
Part A: Find the constant of proportionality. Show every step of your work. (4 points)