For the first 1 you do 180 - 115 = 65
I think for 2 same concept as linear is add up to 180 so 180 - 105 = 75
Triangle sum theorem is 180
To get 7 you subtract 180 - 65 - 75 = 40
7 and 6 are vertical angles I believe so 6 would = 40
Vertical angles are congruent so that is why 6=7
