X3082

RADICAL CENTER OF EXTERNAL MALFATTI CIRCLES

Let (OA) be the I-excircle of triangle IBC, where I = X1, and define (OB) and (OC) cyclically. Let A' be the touchpoint of (OA) and side BC, and define B' and C' cyclically. Let A″ be the insimilicenter of (OB) and (OC), and define B″ and C″ cyclically. The lines A'A″, B'B″, C'C″ concur in X3082. (Randy Hutson, July 11, 2019)
< A B C >: Reference Triangle △ABC [ A B ]: Sideline AB (Base c = 1) [ B C ]: Sideline BC (Side a) [ C A ]: Sideline CA (Side b) { 8, 178 }: Central Line L(8, 178) { 174, 176 }: Central Line L(174, 176) A = Vertex A (0.0000, 0.0000) B = Vertex B (1.0000, 0.0000) C = Vertex C (0.6122, 0.5999) X_8 = NAGEL POINT (0.4694, 0.1333) X_178 = 2nd MID-ARC POINT (0.5439, 0.2098) X_174 = YFF CENTER OF CONGRUENCE (0.5813, 0.2549) X_176 = EQUAL DETOUR POINT (0.5803, 0.2537) X_3082 = RADICAL CENTER OF EXTERNAL MALFATTI CIRCLES (0.4624, 0.1261) A B C X8 X178 X174 X176 X3082 (a, b, c) = (5, 6, 7) | AB = 1

X3082 (RADICAL CENTER OF EXTERNAL MALFATTI CIRCLES) constructed on acute reference triangle \((a, b, c) = (5, 6, 7)\) with unit baseline AB = \(1\).

Constructed Elements

Trilinears: \(f(A,B,C) : f(B,C,A) : f(C,A,B)\), where \(f(A,B,C) = 1/(1 - \cos A/2)\)
Barycentrics: \((\sin A)f(A,B,C) : (\sin B)f(B,C,A) : (\sin C)f(C,A,B)\)
Search Value (6, 9, 13): \(4.611475589035\)
▸ Incident Central Lines2 lines

{8, 178}, {174, 176}