ta có:\(\widehat{aOb}\) = 180
\(\Rightarrow\)3 x \(\widehat{aOc}\)=180
\(\Rightarrow\)\(\widehat{aOc}\)=180 : 3 = 60
\(\Rightarrow\)\(\widehat{aOc}\)=\(\widehat{bOd}\)= 60 (2 góc đối đỉnh)
ta có: \(\widehat{aOc}\)+\(\widehat{cOb}\)= 180 (2 góc kề bù)
\(\Rightarrow\)60 + \(\widehat{cOb}\)= 180
\(\Rightarrow\)\(\widehat{cOb}\)= 180 - 60 = 120
\(\Rightarrow\)\(\widehat{aOd}\)=\(cOb\)= 120 (2 goc đối đỉnh)
Vậy \(\widehat{aOc}\)= 60;\(\widehat{cOb}\)= 120;\(\widehat{bOd}\)= 60;\(\widehat{aOd}\)=120