D B
E
1
3
A
IC
Points A. B, and form a triangle. Complete the statements to prove that the sum of the interior angles of AABCIS
Statement
Reason
Points A, B, and Cform a triangle.
given
Let DE be a line passing through B and parallel to AC. definition of parallel lines
23 25 and 2124
mz1 = m24 and mz3 = m25
m24+ m_2 + m25 = 180°
pight li
Alternate Interior Angles Theorem
m2 1 + m2 + m23 = 180°
Alternate Exterior Angles Theorem
Corresponding Angles Theorem
Reset
Congruent angles have equal measures