Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of abc is 180°
reason
statement
points a, b, and c form a triangle.
given
let de be a line passing through b and parallel to ac. definition of parallel lines
232 25 and 21 – 24
m21 = m 24 and m23=m25
m24+ m2 + m25 = 180°
m21 + m22 + m23 = 180°
angle addition and definition of a straight line
substitution
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