\(\widehat{xOz}+\widehat{zOy}=180^0\)(hai góc kề bù)
nên \(\dfrac{5}{4}\widehat{zOy}+\widehat{zOy}=180^0\)
\(\Leftrightarrow\widehat{zOy}=80^0\)
\(\Leftrightarrow\widehat{xOz}=100^0\)
\(\widehat{xOz}=\widehat{yOt}=100^0\)(hai góc đối đỉnh)
\(\widehat{zOy}=\widehat{xOt}=80^0\)(hai góc đối đỉnh)