olymmath

JBMO-SL 2019 G2

    Let ABCA B C be a triangle and let ω\omega be its circumcircle. Let ℓB\ell_{B} and ℓC\ell_{C} be two parallel lines passing through BB and CC respectively. The lines ℓB\ell_{B} and ℓC\ell_{C} intersect with ω\omega for the second time at the points DD and EE respectively, with DD belonging on the arc ABA B, and EE on the arc ACA C. Suppose that DAD A intersects ℓC\ell_{C} at FF, and EAE A intersects ℓB\ell_{B} at GG. If O,O1O, O_{1} and O2O_{2} are the circumcenters of the triangles ABC,ADGA B C, A D G and AEFA E F respectively, and PP is the center of the circumcircle of the triangle OO1O2O O_{1} O_{2}, prove that OPO P is parallel to ℓB\ell_{B} and ℓC\ell_{C}.

    Dataset text NuminaMath olympiads. Quoted with source.

    Solutions

    No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.

    Add a solution

    Locator jbmo-sl/2019/g2 · Tag BJ71G69RZS · Edit this page on GitHub · Keys: j next, k previous