Respuesta :

[tex]\Theta[/tex]/[tex]\theta[/tex] is "theta", not "delta" (which is [tex]\Delta[/tex]/[tex]\delta[/tex])

By definition of cosine,

[tex]\cos\theta=\dfrac{19}{23}\implies\theta=\cos^{-1}\dfrac{19}{23}\approx34.3^\circ[/tex]