Abstract: Most graphics packages allow users to create arcs from both circles and ellipses. Unfortunately, in some packages the elliptical arcs are drawn incorrectly, resulting in distorted arcs that do not begin and end at the specified angles. Based on the hypothesis that this is because the system is drawing elliptical arcs by non-uniformly scaling circular arcs, this paper presents the geometry for pre-distorting the desired angles so that the final image is correct.