Verified answer

Answer:

b) 20°

Step-by-step explanation:

In triangle, the sum of all angles is equal to 180°

angle A + angle B + angle C = 180° (i)

Given: [angle A + angle B = 80°]

From (i):

80° + angle C = 180°

angle C = 100°

Given: [angle B + angle C = 120°]

angle B + 100° = 120°

angle B = 20°

Ans: angle B = 20°

Step-by-step explanation:

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