Question

please solve this problem

Answer 1

Answer:

Step-by-step explanation:

1) ∠A+∠B=140°

70°+∠B=140°

∠B=70°

2) ∠A=80°

3) ∠A=180°-(90°+30°)

∠A=60°

4) ∠A=180°-(90°+40°)

∠A=50°

Answer 2

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[1]. ∠A = 70°; Ext ∠C = 140°

Since, ∠C = ∠A + ∠B

∠B = ∠C-∠A = 140-70 = 70°

Thus, ∠B = 70°

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[2]. Ext ∠C = 140°

Thus, Int.∠C  = 180-140 = 40°

Ext. ∠B = 120°

Thus, Int ∠B = 180-120 = 60°

∠A = 180 - 40 - 60 = 180 - 100 = 80°

Thus, ∠A = 80°

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[3]. ∠B = 90°; ∠C = 30°

∠A = 180 - 90 - 30 = 180 - 120 = 60°

Thus, ∠A = 60°

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[4]. Ext. ∠B = 90°; Int ∠C = 40°

∠A = 90-40 = 50°

Thus, ∠A = 50°

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