The student used the wrong trig ratio. They should use cosine instead.
[tex]\cos(\text{angle}) = \frac{\text{adjacent}}{\text{hypotenuse}}\\\\\cos(x) = \frac{9}{29}\\\\x = \cos^{-1}\left(\frac{9}{29}\right)\\\\x \approx 71.9^{\circ}\\\\[/tex]
If the student wanted to use sine, then they would need to use the pythagorean theorem to find the opposite side first. I recommend using cosine since it's faster. Make sure your calculator is in degree mode.
