$xy∩zt≡O$
$⇒\widehat{xOz}=\widehat{yOt}=37^o$ (đối đỉnh)
Ta có: $\widehat{xOz}+\widehat{yOz}=180^o$ (kề bù)
mà $\widehat{xOz}=37^o$
$⇒\widehat{yOz}=180^o-37^o=143^o$
mà $xy∩zt≡O$
$⇒\widehat{yOz}=\widehat{xOt}=143^o$ (đối đỉnh)
Vậy $\widehat{xOz}=\widehat{yOt}=37^o$
$\widehat{yOz}=\widehat{xOt}=143^o$