ملتقى الارتفاعات في المثلث القائم الزاوية تقع عند رأس الزاوية القائمة. قانون المثلث قائم الزاوية

Todor Zaharinov, "The Simson triangle and its properties", Forum Geometricorum 17 2017 , 373--381	"The History of the Solution of the Cubic Equation"
"Inversion in a Circle" and "Inversion of Lines and Circles	Youschkevitch, chief editor: Boris A

العلاقات في المثلث

Washington, DC, USA: Mathematical Association of America.

ارتفاع (مثلث): , The Elements of Geometry, in Eight Books; or, First Step in Applied Logic London, Longmans, Green, Reader and Dyer, 1874 , p
طولا ضلعي القائمة في المثلث القائم أدناه هما: A Distorted View of Geometry
نقطة التقاء الارتفاعات في المثلث: Dragutin Svrtan and Darko Veljan, "Non-Euclidean versions of some classical triangle inequalities", Forum Geometricorum 12 2012 , 197—209

See in particular the bottom of p	, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus• Altshiller-Court, Nathan, College Geometry, Dover, 2007
Altshiller-Court, Nathan, College Geometry, Dover, 2007 orig	Advanced Euclidean Geometry: An Elementary treatise on the geometry of the Triangle and the Circle

The Associated Harmonic Quadrilateral, Paris Pamfilos, Forum Geometricorum, Volume 14 2014 15—29.

العمود الساقط من رأس المثلث القائم: — The Cosmos: A Historical Perspective 2006 — p
نقطة التقاء الارتفاعات في المثلث: "On the Equations and Properties: 1 of the System of Circles Touching Three Circles in a Plane; 2 of the System of Spheres Touching Four Spheres in Space; 3 of the System of Circles Touching Three Circles on a Sphere; 4 of the System of Conics Inscribed to a Conic, and Touching Three Inscribed Conics in a Plane"
نقطة التقاء الارتفاعات في المثلث: Burago 2001 [1994], "Isoperimetric inequality", in Hazewinkel, Michiel ed

The Secrets of Triangles, Prometheus Books, 2012
Geometry revisited, volume 19 ofNew MathematicalLibrary	"Circles: A Mathematical View, rev

Novi Commentarii academiae scientarum imperialis Petropolitanae.