Hello!
This is a question relating trigonometry to unknown sides.
Here we can use the law of sines, which state that if a triangle is a right triangle, the ratio between a side and the sin of its opposite angle will be equal to any other ratio of the same type.
This means that we can set up this equation.
![(17)/(sin(90))=(AC)/(sin(38))](https://img.qammunity.org/2022/formulas/mathematics/high-school/4fj5osdwawybzowauoww039qchfj24jv81.png)
![AC=17sin(38)](https://img.qammunity.org/2022/formulas/mathematics/high-school/9sq0tc5v64xn1d9y48l4x69mhkxkwm93zk.png)
Be sure to be on degrees if you're on a calculator.
![AC=10.47](https://img.qammunity.org/2022/formulas/mathematics/high-school/ace4cm55lqf1cdy7y8hqsf8am0rfbska7s.png)
Hope this helps!