Answer: First option.
Step-by-step explanation:
You need to remember the following Trigonometric Identity:
[tex]cos\alpha =\frac{adjacent}{hypotenuse}[/tex]
In this case, you can identify in the figure that:
[tex]\alpha =35\°\\adjacent=9\\hypotenuse=x[/tex]
Then you must substitute these values into [tex]cos\alpha =\frac{adjacent}{hypotenuse}[/tex]:
[tex]cos(35\°) =\frac{9}{x}[/tex]
Finally, you need to solve for "x" in order to find its value. This is:
[tex](x)(cos(35\°))=9\\\\x=\frac{9}{cos(35\°)}\\\\x=10.98[/tex]
Rounding the result to the nearest tenth, you get:
[tex]x\approx11[/tex]
