1)AOB+BOC+COD+DOA sunt unghiuri in jurul unui punct, deci suma lor va fi de 360°
90°(unghi drept) +60°+50°+m COD=360°
COD=360°-(90+50+60)
COD=360-200
COD=160°
ABC+CBD+DBE+EBA=360°
EBA=ABC+2°=>ABC=EBA-2
=CBD+4°=>CBD=EBA-4
=DBE+6°=>DBE=EBA-6
EBA-2+EBA-4+EBA-6+EBA=360°
4EBA-12°=360°
4EBA=360°-12°
4EBA=348°
EBA=348°:4
EBA=87°
ABC=87-2=85°
CBD=87-4=83°
DBE=87-6=81°
