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.

The negative of lead aVR (R for right arm) is at +30 degrees; the positive of lead aVR is actually at -150 degrees. Although memorizing the above picture is crucial to accurately determining axis ...