Ta có: \(\widehat{zAn}=\widehat{xAy}=36^0\) (đối đỉnh)
\(\widehat{xAz}+\widehat{xAy}=180^0\) (kề bù)
\(\Rightarrow\widehat{xAz}=180^0-\widehat{xAy}=180^0-36^0=144^0\)
\(\Rightarrow\) \(\widehat{nAy}=\widehat{xAz}=144^0\) (đối đỉnh)
\(\widehat{zAn}=\widehat{xAy}=36^o\) (Đối đỉnh).
\(\widehat{zAy}=180^o\) (Góc bẹt).
\(\widehat{xAn}=180^o\) (Góc bẹt).
\(\widehat{xAz}+\text{}\widehat{xAy}=180^o.\\ \Rightarrow\widehat{xAz}+36^o=180^o.\\ \Rightarrow\widehat{xAz}=144^o.\)
\(\widehat{xAz}=\widehat{yAn}=144^o\) (Đối đỉnh).











