IMO 1985 LL USA85

Let CD be a diameter of circle K. Let AB be a chord that is

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IMO 1985 LL USA85

Origin: USA

Problem

Let CD be a diameter of circle K. Let AB be a chord that is parallel to CD. The line segment AE, with E on K, is parallel to CB; F is the point of intersection of line segments AB and DE. The line segment FG, with G on DC, extended is parallel to CB. Is GA tangent to K at point A?