Cho hình vẽ sau. Biết góc $xOy'$  đối đỉnh với góc $x'Oy,$ biết \(\widehat {xOy'} = {\widehat O_1} = {165^o}\). Tính các góc đỉnh O (khác góc bẹt).

\(\widehat {z'At'}\)

\(\widehat {z'At}\)     

\(\widehat {zAt'}\) \(\)

\(\widehat {zAt}\)

$30^\circ$

$120^\circ$

$90^\circ$

$60^\circ$

$\widehat {x'Oy} = 135^\circ $                   

$\widehat {x'Oy'} = 45^\circ $

$\widehat {xOy'} = 135^\circ $

$\widehat {x'Oy'} = 135^\circ $

\(\widehat {zOt} = \widehat {z'Ot'} = 72^\circ \)

\(\widehat {zOt} = \widehat {z'Ot'} = 30^\circ \)

\(\widehat {zOt} = \widehat {z'Ot'} = 36^\circ \)

\(\widehat {zOt} = 72^\circ ;\,\widehat {z'Ot'} = 36^\circ \)

\(\widehat {xOy'}\,\,;\,\,\widehat {x'Oy'}\)                

\(\widehat {xOy}\,\,;\,\,\widehat {x'Oy'}\)

\(\widehat {xOy'}\,\,;\,\,\widehat {x'Oy}\)  

\(\widehat {xOy'}\,\,;\,\,\widehat {xOy}\)

\(\widehat {BON} = \widehat {DON} = 25^\circ \)           

\(\widehat {BON} = \widehat {DON} = 30^\circ \)           

\(\widehat {BON} = \widehat {DON} = 60^\circ \)           

\(\widehat {BON} = \widehat {DON} = 45^\circ \)