Let ABC be a triangle, and Ma,Mb,Mc be the midpoints of BC,CA,AB, respectively. Extend MbMc so that it intersects ⊙(ABC) at P. Let AP and BC intersect at Q. Prove that the tangent at A to ⊙(ABC) and the tangent at P to ⊙(PQMa) intersect on line BC.(Li4) geometryconcurrencyTangentsmidpoint