Points A, B, and C form a triangle. Complete the statements to prove that the sum of the interior angles of AABC is 180º. Statement
Reason
given
Points A, B, and C form a triangle.
Let DE be a line passing through Band parallel to AC
definition of parallel lines
23 25 and 21 - 24
mZ1 = m 24 and 23 = m 25
angle addition and definition of a straight line
m24+ m2 + m 25 = 180°
m21 + m2 + m23 = 180°
substitution