5
Since the given lines are parallel, then by the alternate interior angle theorem, m/1 = 90°, m/1 + m/2 = m/5, and 23 24
Congruent angles have equal measures.
substitution
definition of straight angle
Statement
90° +m/2+m/4 = 180°
m/3= m/4
m/1+m/2+m/3 <= 180°
transitive property
definition of linear pair
Reason
