Prove that the sum of angles of triangle is 180

1.	Prove that the sum of angles of triangle is 180
Answer» FROM\xa0Δ ABC\xa0draw a\xa0parallel line DE ║\xa0BC∠DAB +\xa0∠BAC +∠CAE = 180∠DAB =\xa0∠ABC (ALTERNATE ANGLES ARE EQUAL)∠CAE =\xa0∠ACB (ALTERNATE ANGLES ARE EQUAL)SO,\xa0∠ABC +\xa0∠ACB +\xa0∠BAC =180

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