D l / M
l /
l /
l O/
A ------------------------ -l/------------------------------ B
l
l
l
l C
AOC si BOC=unghiuri suplementare, adica AOC+BOC=180
2AOC=3BOC
AOC+BOC=180 l x2
2AOC+2BOC=360
3BOC+2BOC=360
5BOC=360
BOC=72
AOC=3/2 xBOC=3/2 x72=108
BOD=AOC (unghiuri opuse)=108
BOM=BOD/2=108/2=54 (OM= bisectoare)
COM=BOC+BOM=72+54=124