Question

I dont understand this

Answer 1

Answer: First option.

Step-by-step explanation:

You need to remember the following Trigonometric Identity:

$cos\alpha =\frac{adjacent}{hypotenuse}$

In this case, you can identify in the figure that:

$\alpha =35\°\\adjacent=9\\hypotenuse=x$

Then you must substitute these values into $cos\alpha =\frac{adjacent}{hypotenuse}$:

$cos(35\°) =\frac{9}{x}$

Finally, you need to solve for "x" in order to find its value. This is:

$(x)(cos(35\°))=9\\\\x=\frac{9}{cos(35\°)}\\\\x=10.98$

Rounding the result to the nearest tenth, you get:

$x\approx11$