A = 121, Vertical Angles Theorem B = 59, Supplementary Angles Theorem C = 59, Vertical Angles Theorem D = 55, Alternate Interior Angles Theorem E = 4, sum of all angles in a triangle is 180 F = 73, sum of all angles in a triangle is 180 G = 73, Alternate Interior Angles Theorem H = 48, Alternate Interior Angles Theorem I = 4, Alternate Interior Angles Theorem
