Answer:
cos B = 0.89
Step-by-step explanation:
If ∠A and ∠B are complementary then: ∠A + ∠B = 90°
Given that sin A = 8/9 then A can be computed with the inverse of sine as follows:
∠A = arcsin(8/9) = 62.7°
Then:
62.7° + ∠B = 90°
∠B = 90° - 62.7°
∠B = 27.3°
Finally,
cos 27.3° = 0.89