Answer:
25.3°
Explanation:
You want the measure of angle B in triangle ABC with A=28°, a=22, b=20.
Law of Sines
The law of sines tells you that side lengths are proportional to the sine of the opposite angle. Fill in the proportion and solve for the angle.
sin(B)/b = sin(A)/a
sin(B) = b·sin(A)/a . . . . multiply by b
Use the inverse sine function to find the angle from its sine.
B = arcsin(b/a·sin(A)) = arcsin(20/22·sin(28°)) ≈ arcsin(0.426792)
B ≈ 25.3°