A very short and simple proof of ``the most elementary theorem" of euclidean geometry - Mowaffaq Hajja We give a very short and simple proof of the fact that if ABB' and AC'C are straight lines with BC and B'C' intersecting at D, then AB + BD = AC' + C'D if and only if AB' + B'D = AC + CD. The ``only if" part is attributed to Urquhart, and is referred to by Dan Pedoe as ``the most elementary theorem of Euclidean geometry". ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education
