Question

"1.Provide the reasons for the proof.

Answer 1

Assuming you are given a picture of intersecting lines. 

Switch the reasons for b) and c) 
b) the angles form a linear pair , from the picture, so this is linear pair postulate
C) Then the measures add to 180, because they are supplementary. Defn of supplementary. 
E) you have divided both sides of the equation by 2; or multiplied by 1/2; multiplication property of equality 
F) definition of right angle 
G) definition of perpendicular 

I hope my answer has come to your help. Have a nice day ahead and may God bless you always!