In the above figure, the lines , , and are tangent to the parabola at points , , and , respectively. Then (Wells 1991). Moreover, thecircumcircle of passes through the focus (Honsberger 1995, p. 47). In addition, the foot of the perpendicular to a tangent to a parabola from the focus always lies on the tangent at the vertex (Honsberger 1995, p. 48).