Angles 1,2,3,and 4 are formed by two intersecting lines. State the single fact necessary to prove that m<1 + m<2= m<2+ m<3

127

whether it's diameter, or radius, i believe if i remember correctly from school, every amount has to always add up to 180. so if you take 53, and starting adding, long story short, taking 127 and adding it to 53, gives you 180.