It is also possible to have a conversion graph to switch between units that are not directly proportional. For example, temperature can be measured in degrees Centigrade (°C) and degrees Fahrenheit ...

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 ...