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ABC A1B1C1 ∠ A = ∠ A1, ∠ B = ∠ B1, AB = A1B1.
A1B2C2 , ABC. B2 A1B1, 2 A1B1, 1. A1B2 = A1B1, B2 B1. ∠ B1A1C2 = ∠ B1A1C1 ∠ A1B1C2 = ∠ A1B1C1, A1C2 A1C1, B1C2 B1C1. , 2 1. A1B1C1 A1B2C2, , ABC. .
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