Answer: Last option.
Step-by-step explanation:
You need to remember the following identity:
[tex]sin\alpha=\frac{opposite}{hypotenuse}[/tex]
In this case, we can observe that:
[tex]\alpha=30\°\\opposite=4\\hypotenuse=x[/tex]
Now you must substitute these values into [tex]sin\alpha=\frac{opposite}{hypotenuse}[/tex] and solve for the hypotenuse. Then:
[tex]sin(30\°)=\frac{4}{x}\\\\(x)(sin(30\°))=4\\\\x=\frac{4}{sin(30\°)}\\\\x=8[/tex]
