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The Five Circle Theorem

The Five Circle Theorem.

Miquel's Five-Circle Theorem is among a sequence of wonderful theorems in plane geometry bearing his name. It states that

By starting from a pentagon in the plane, one can construct a 5-star whose ertices are the intersections of the non-neighboring edges of the pentagon. If five circles are drawn such that each circle circumscribes a riangular corner of the star, then the neighboring circles intersect at five new points which are cocircular.

Note: You can drag free points (red points) to see the effect.

See Also:

1. The proof of this theorem with Full-Anlge Method.
2. The proof with Deductive Database Method.