INSTITUTO DE MATEMÁTICA
HJB --- GMA --- UFF

X(74)
(ISOGONAL CONJUGATE OF EULER INFINITY POINT)


Click here to access the list of all triangle centers.

Interactive Applet

You can move the points A, B and C (click on the point and drag it).
Press the keys “+” and “−” to zoom in or zoom out the visualization window and use the arrow keys to translate it.

You can also construct all centers related with this one (as described in ETC) using the “Run Macro Tool”. To do this, click on the icon Run Macro Tool, select the center name from the list and, then, click on the vertices A, B and C successively.

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Download all construction files and macros: tc.zip (10.1 Mb).
This applet was built with the free and multiplatform dynamic geometry software C.a.R..


Information from Kimberling's Encyclopedia of Triangle Centers

Trilinears           1/(cos A - 2 cos B cos C) : 1/(cos B - 2 cos C cos A) : 1/(cos C - 2 cos A cos B)
                                    = f(a,b,c) : f(b,c,a) : f(c,a,b), where f(a,b,c) = a/[2a4 - (b2 - c2)2 - a2(b2 + c2)]

Barycentrics    a/(cos A - 2 cos B cos C) : b/(cos B - 2 cos C cos A) : c/(cos C - 2 cos A cos B)

As the isogonal conjugate of the point in which the Euler line meets the line at infinity, X(74) lies on the circumcircle.

X(74) = circumcircle-antipode of X(110)
X(74) is the point of intersection, other than A, B, and C of the circumcircle and Jerabek hyperbola.

In Hyacinthos 8129 (10/4/03), Floor van Lamoen noted that if X(74) is denoted by J, then each of the points A,B,C,J is J of the other three, in analogy with the well known property of orthocentric systems (that is, each of the points A,B,C,H is the orthocenter of the other three).

X(74) lies on these lines:
2,113    3,110    4,107    6,112    20,68    24,64    30,265    35,73    54,185    65,108    67,935    69,99    71,101    72,100    98,690    187,248    477,523    511,691    512,842    550,930

X(74) = reflection of X(I) in X(J) for these (I,J): (4,125), (110,3), (146,113), (399,1511)
X(74) = isogonal conjugate of X(30)
X(74) = complement of X(146)
X(74) = anticomplement of X(113)
X(74) = cevapoint of X(I) and X(J) for these (I,J): (15,16), (50,184)
X(74) = crosssum of X(I) and X(J) for these (I,J): (3,399), (616),617)
X(74) = X(I)-cross conjugate of X(J) for these (I,J): (186,54), (526,110)


This is a joint work of
Humberto José Bortolossi, Lis Ingrid Roque Lopes Custódio and Suely Machado Meireles Dias.

If you have questions or suggestions, please, contact us using the e-mail presented here.

Departamento de Matemática Aplicada -- Instituto de Matemática -- Universidade Federal Fluminense




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