## Elementary Geometry for College Students (7th Edition)

The way we arrive at this auxiliary being overdetermined is because it is impossible for us to satisfy all of the conditions the question is calling for. The question is calling for us to draw a line that crosses through the vertex of C to the midpoint of $\overline{AB}$ AND is perpendicular to $\overline{AB}$. This is impossible to satisfy all of the conditions so this auxiliary line would be described as overdetermined.