Answer:
1. m<1 + <2 = m<4; given
2. m<3 + m<4 = 180; linear pair postulate
3. m<1 +m<2 + m<3 = 180; substitution property
1. <1 is congruent to <4; given
2. <1 is congruent to <2, <3 is congruent to <4; vertical angle congruency theorem
3. <2 has to be congruent to <3; transitive property
Explanation: