Let's first draw a diagram of the situation
Let's call the missing angle a, then using the definition of the sine function, we have that
![\sin (a)=(75)/(120)](https://img.qammunity.org/2023/formulas/mathematics/college/ubqq0zntdmrlv79xjehf8dsgx11rdj9qvp.png)
then, we can take inverse sine in both sides of the equality to clear a
![a=\sin ^(-1)((75)/(120))=38,68218745](https://img.qammunity.org/2023/formulas/mathematics/college/5lu8pkhfah10l4gj1wk3reisiatm8jv32q.png)
and rounding to the nearest degree, the answer will be 39 degrees.