| | ENCYCLOPEDIA OF TRIANGLE CENTERS |
 | | X(1) is the point of concurrence of the interior angle bisectors of ABC; the point inside ABC whose distances from sidelines BC, CA, AB are equal. |
| | Construct the equilateral triangle BA'C having base BC and vertex A' on the negative side of BC; similarly construct equilateral triangles CB'A and AC'B based on the other two sides. |
| | Let U and V be the points on sideline BC met by the interior and exterior bisectors of angle A. The circle having diameter UV is the A-Apollonian circle. |
| faculty.evansville.edu /ck6/encyclopedia/ETC.html (10360 words) |
