Explanation:
Use SOH-CAH-TOA.
Sine = Opposite / Hypotenuse
Cosine = Adjacent / Hypotenuse
Tangent = Opposite / Adjacent
Let's start with #12. The hypotenuse is 18. The side adjacent to ∠B is 6. Since we have the adjacent side and hypotenuse, we should use cosine.
cos B = 6/18
Solving for B:
B = cos⁻¹(6/18)
Using a calculator:
B ≈ 70.5°
Now let's do #14. The side adjacent to ∠B is 19, and the side opposite of ∠B is 22. Since we have the adjacent side and opposite side, we should use tangent.
tan B = 22/19
Solving for B:
B = tan⁻¹(22/19)
Using a calculator:
B ≈ 49.2°