6. since sum of angels in a triangle = 180 therefore 180 - (30 + 20) = 130 therefore angle ? = 130°, due to being a vertically opposite angle.
7. since straight angles have a sum of 180 therefore 180 - 137 = 43 since sum of triangle angles = 180 therefore 180 - (43 + 102) = 35 again since straight angles have a sum of 180 therefore exterior angle ? = 180 - 35 = 145°
