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.
Information from Kimberling's Encyclopedia of Triangle Centers |
Trilinears 1 + cos(B - C) : 1 + cos(C - A) : 1 + cos(A - B)
= f(A,B,C) : f(B,C,A) : f(C,A,B), where f(A,B,C) = cos2(B/2 - C/2)
= g(a,b,c) : g(b,c,a) : g(c,a,b), where g(a,b,c) = bc(b + c)2/(b + c - a)Barycentrics a(1 + cos(B - C)) : b(1 + cos(C - A)) : c(1 + cos(A - B))
= h(a,b,c) : h(b,c,a) : h(c,a,b), where h(a,b,c) = (b + c)2/(b + c - a)Let A'B'C' be the touch points of the nine-point circle with the A-, B-, C- excircles, respectively. The lines AA', BB', CC' concur in X(12).
X(12) lies on these lines:
1,5 2,56 3,498 4,55 7,1268 10,65 17,203 18,202 30,35 33,235 34,427 36,140 37,225 38,1393 40,1836 42,1834 54,215 57,1224 63,1454 71,1901 79,484 85,120 108,451 115,1500 116,1362 117,1364 121,1357 123,1359 124,1361 125,1425 141,1469 171,1399 172,230 201,756 208,1360 221,1853 228,407 281,1118 313,349 354,1210 377,1259 381,1479 431,1824 443,1466 474,1470 485,1124 486,1124 499,999 603,750 611,1352 908,960 942,1209 946,1532 968,1904 1015,1506 1038,1368 1091,1109 1125,1319 1213,1400 1452,1892 1594,1870 1697,1699 1861,1887 1877,1883X(12) is the {X(1),X(5)}-harmonic conjugate of X(11).
X(12) = isogonal conjugate of X(60)
X(12) = isotomic conjugate of X(261)
X(12) = complement of X(2975)
X(12) = X(10)-Ceva conjugate of X(201)
X(12) = crosssum of X(58) and X(1437)
X(12) = X(I)-beth conjugate of X(J) for these (I,J): (10,12), (1089,1089)