a prabola and a tangent@@

@There is a parabola(blue).A red line is a tangent on point P.Line PB is a perpendicular to line OB.

Move point P to find the geometric quality of the three segment length (OA,AB,PB).
@You can also move points (P,Q,R) on CABRI.

Download CABRIU data (d34) from here.