Question

Please help me with this

Answer 1

Answer: second option.

Step-by-step explanation:

By definition, the measure of any interior angle of an equilateral triangle is 60 degrees.

Based in this, we know that the measusre of the angle ∠SRT is:

$\angle SRT=\frac{60\°}{2}=30\°$

The, we can find the value of "y":

$y+12=30\\y=30-12\\y=18$

To find the value of "x", we must use this identity:

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

In this case:

$\alpha=30\°\\adjacent=x\\hypotenuse=RU=RS=4$

Substituting values and solving for "x", we get:

$cos(30\°)=\frac{x}{4}\\\\4*cos(30\°)=x\\\\x=\sqrt{12}$