Plot points with coordinates where \(x\) and \(y\) are equal. Three points are sufficient, but more can be plotted. Draw a line through the plotted points. If \(x\) is positive, \(y\) is negative. If ...

Physicists like to share the legend of a professor who asked students how they might determine the height of a building using a barometer. The story goes on to list some of the ways you might do that.