Hello there. To solve this question, we'll have to remember some properties about trigonometric functions.
Given the following triangle:
We want to find the angle x.
For this, we'll use the cosine function.
It relates the adjacent side to the angle to the hypotenuse of the right triangle by the following ratio:
In this case, the adjacent side measures 3.9 and the hypotenuse measures 8.5. Plugging in these values in the fraction, we'll have:
Using a calculator, the value of the fraction is approximately equal to:
Again, with a calculator, we apply the function cos^-1 to calculate the value of x:
This is the approximate value of the angle.