Question

definition of a right angle
division property of equality
addition property of equality
segment addition postulate
definition of linear pairs
linear pair property
Substitution Property of equality
definition of supplementary angles
Can some1 show me how to do proofs these are the possible choices above.
m<1 + m<2 = 180
m<1 + m<1 = 180
2(m<1) = 180
m<1 = 90
if you can just pick 1 and show me step by step how to do it that would be great!
http://i.imgur.com/2PYWpL6.png?1