MathDB
(ASG) tangent to (J)

Source: 6th XMO (China) p5 https://artofproblemsolving.com/community/c3192772_geometry_regional_china

April 7, 2024
tangent circlesgeometry

Problem Statement

As shown in the figure, O\odot O is the circumcircle of ABC\vartriangle ABC, J\odot J is inscribed in O\odot O and is tangent to ABAB, ACAC at points DD and E respectively, line segment FGFG and O\odot O are tangent to point AA, and AF=AG=ADAF =AG=AD, the circumscribed circle of AFB\vartriangle AFB intersects J\odot J at point SS. Prove that the circumscribed circle of ASG\vartriangle ASG is tangent to J\odot J. https://cdn.artofproblemsolving.com/attachments/a/a/62d44e071ea9903ebdd68b43943ba1d93b4138.png