3:
Qua O, kẻ tia Oz//Px(Oz và Px nằm khác phía nhau)
Oz//Px
Px//Qt
Do đó: Oz//Qt
Oz//Px
=>\(\widehat{zOP}=\widehat{xPO}\)(hai góc so le trong)
=>\(\widehat{zOP}=35^0\)
\(\widehat{zOP}+\widehat{zOQ}=\widehat{POQ}\)
=>\(\widehat{zOQ}=55^0\)
Oz//Qt
=>\(\widehat{zOQ}=\widehat{tQO}\)(so le trong)
=>\(\widehat{Q}=55^0\)