Mowaffaq Hajja and Margarita Spirova, A characterization of the centroid using June Lester's shape function,
Forum Geometricorum, 6 (2006) 53--55.

Abstract: The notion of triangle shape is used to give another proof of the fact that if P  is a point inside triangle ABC and if  the cevian triangle of P is similar to ABC in the natural order, then P is the centroid.

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