Select the correct answer from each drop-down menu. Points A B, and Cform a triangle. Complete the statements to prove that the sum of the interior angles of AABC is 180°
Statement
Reason
Points A B, and form a triangle.
given
Let DE be a line passing through Band parallel to AC. definition of parallel lines
23 - 25 and 21 24
m21 = m 24 and m23 = m 25
m24+ m22+ m25 = 180°
angle addition and definition of a straight line
substitution
mZ1 + Z2 + m 23 = 180°