Frank M. Jackson, Soddyian triangles,
Forum Geometricorum, 13 (2013) 1--6.

Abstract. A Soddyian triangle is a triangle whose outer Soddy circle has degenerated into a straight line. This paper examines some properties of Soddyian triangles, including the facts that no Soddyian triangle can be right angled and all integer Soddyian triangles are Heronian. A generating formula is developed to produce all primitive integer Soddyian triangles. A ruler and compass construction of a Soddyian triangle concludes the paper.

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