What is the measure of

Answer:
Step-by-step explanation:
To find out ∠B, we need to find out what is ∠A. We are given one clue that the outer angle of ∠A is 143°. Can we use this clue and find out ∠A? Let's find out!
Since we have found ∠A, we can now find ∠B.
Conclusion:
We have finally found out our answer and our answer is '∠B = 82°'.
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