The intouch triangle and the OI-line - Eric Danneels We prove some interesting results relating the intouch triangle and the OI line of a triangle. We also give some interesting properties of the triangle center X(57), the homothetic center of the reference triangle and the orthic triangle of the intouch triangle. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education