A line graph has Number of Turns of a Large Tire on the x-axis, and Number of Turns of a Small Tire on the y-axis. For every 2 turns on a large tire, there are 10 turns on a small tire; 4, 20; 6, 30; 8, 40. Find the constant of proportionality from the proportional relationship shown on the graph.

The median of a data set is the measure of center that is found by adding the data values and dividing the total by the number of data values that is the value that occurs with the greatest frequency that is the value midway between the maximum and minimum values in the original data set that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude