HJB --- GMA --- UFF


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: (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           sec(A/2) csc(A/2 + π/3) : sec(B/2) csc(B/2 + π/3) : sec(C/2) csc(C/2 + π/3)
Barycentrics    sin A sec(A/2) csc(A/2 + π/3) : sin B sec(B/2) csc(B/2 + π/3) : sin C sec(C/2) csc(C/2 + π/3)

Suppose X and Y are triangle centers. Let

YA = (Y of the triangle XBC),
YB = (Y of the triangle XCA),
YC = (Y of the triangle XAB).

Let A' = (XYA intersect BC), and define B' and C' cyclically. In

Clark Kimberling, "Major Centers of Triangles," Amer. Math. Monthly 104 (1997) 431-438,

Question A is this: for what choices of X and Y do the lines AA', BB', CC' concur? A solution (X,Y) will here be called the (X,Y)-answer to Question A. X(554) is the (X(1),X(13))-answer to Question A. (In the reference, see (9) on page 435, with Y = X(13).)

X(554) lies on these lines: 1,30    7,1082    14,226    75,299

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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