What is that constant of proportionality in the equation? y=4x

In a direct relationship, we have a value y that varies directly with x. We can write that  is equal to the k, the constant of variation. This is the same as the slope, m, in a linear equation.

Here, 4 is the constant of variation. For some number x, y is four times that number—no matter what.

You would plot 83 on the 83 line and you would plot -113 on the -113 line.