Explanation:
The trigonometric function cosine is defined as the following:
where
is any angle in a right triangle,
is the length of the side adjacent to angle
, and
is the length of the hypotenuse of the triangle.
For this problem, we can fill in these values as follows:
To solve for
, we need to take the inverse cosine of each side:
Resolving this with a calculator results in
°, or rounded to the nearest tenth,
°