Bonjour,
[tex]\boxed{\widehat{YXZ}=90^o}\\\\cos(\widehat{XYZ})=\dfrac{XY}{YZ}\\\\cos(\widehat{XYZ})=\dfrac{2}{6}\\\\cos(\widehat{XYZ})=\dfrac{1}{3}\\\\\widehat{XYZ}=\cos^{-1}(\dfrac{1}{3})\\\\\boxed{\widehat{XYZ}\approx71^o}[/tex]
[tex]\\\\sin(\widehat{XZY})=\dfrac{XY}{YZ}\\\\sin(\widehat{XZY})=\dfrac{2}{6}\\\\sin(\widehat{XZY})=\dfrac{1}{3}\\\\\widehat{XZY}=\sin^{-1}(\dfrac{1}{3})\\\\\boxed{\widehat{XZY}\approx19^o}[/tex]