Angle chasing galore

Two intersecting circles with a triangle connecting them. Show that the three red points are collinear.

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Please find here the solution of the author.

Solution by Rik Tangerman using phantom point.

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One reply on “Angle chasing galore”

The picture has mislead some viewers. The point where the orange and purple segments meet can be moved anywhere along the base of the blue triangle.
In particular, the line connecting the red dots is not in general parallel to the base of the blue triangle.

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