Another synthetic proof of the butterfly theorem using the midline in triangle - Tran Quang Hung We give a new synthetic proof of the butterfly theorem, based on the use of midline in triangle, and cyclic quadrilateral. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education