MathDB
concyclic points, Tuymaada juniors 2001

Source: Tuymaada Junior 2001 p3

April 30, 2019
Concyclicgeometryangle bisectorcircumcircle

Problem Statement

Let ABC be an acute isosceles triangle (AB=BCAB=BC) inscribed in a circle with center OO . The line through the midpoint of the chord ABAB and point OO intersects the line ACAC at LL and the circle at the point PP. Let the bisector of angle BACBAC intersects the circle at point KK. Lines ABAB and PKPK intersect at point DD. Prove that the points L,B,DL,B,D and PP lie on the same circle.