## X(133) (X(106)-OF-ORTHIC-TRIANGLE)

 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 , select the center name from the list and, then, click on the vertices A, B and C successively.

 The JRE (Java Runtime Environment) is not enabled in your browser!

This applet was built with the free and multiplatform dynamic geometry software C.a.R..

 Information from Kimberling's Encyclopedia of Triangle Centers

Trilinears           f(A,B,C) : f(B,C,A) : f(C,A,B), where
f(A,B,C) = (sec A) u(A,B,C) v(A,B,C),
u(A,B,C) = (sin 2B - sin 2C)2 + sin 2A sin 2B - sin 2A sin 2C - 2 sin 2B sin 2C,
v(A,B,C) = 2 sin 2A - sin 2B - sin 2C

Barycentrics    g(A,B,C) : g(B,C,A) : g(C,A,B), where g(A,B,C) = (sin A) f(A,B,C)

X(133) lies on the nine-point circle
X(133) = X(106)-of-orthic triangle.

X(133) lies on these lines: 4,74    5,122    53,115    127,381    136,235

X(133) = midpoint of X(4) and X(107)
X(133) = reflection of X(122) in X(5)

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