Roger C. Alperin, Solving Euler's Triangle Problems with Poncelet's Pencil,
Forum Geometricorum, 11 (2011) 121--129.

Abstract.   We determine the unique triangle given its orthocenter, circumcenter and another particular triangle point. The main technique is to realize the triangle as special intersection points of the circumcircle and a rectangular hyperbola in Poncelet's pencil.

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