Question

Find X.
Round to the nearest tenth.

Answer 1

X ≈ 117.9°

Explanation:

The law of cosines formula is given. Solving it for C, we find ...

C = arccos((a^2 +b^2 -c^2)/(2ab))

where a and b are the sides adjacent to the angle of interest.

Here, we have ...

X = arccos((50^2 +55^2 -90^2)/(2·50·55)) = arccos(-2575/5500)

X ≈ 117.9°