Răspuns :
∡COA +∡AOB +∡BOD =180° (unghi alungit)
Daca AO⊥OB ==> ∡AOB = 90°
Deci ∡COA +∡BOD =180° -90° =90°
REZOLVARE
∡COA +∡AOB +∡BOD =180° (UNCHIUL ALUNGIT)
DACA AO⊥OB ==> ∡AOB = 90°
DECI ∡COA +∡BOD =180° -90° =90°
SUCCES
AZI AM FACUT SI NOI PROPLEMA ASTA IN CLASA