Angle B is the linear pairs with 60°, so the size is 180-60=120°
Angle ABC is the linear pair with 120°, so the size is 180-120-60°
Angle A corresponds to angle 60°, so they are equal
Angle BAC is the linear pair with angle A and angle 70°, so 180-(60+70)=50°
Angle ACB is 180-(50+60) = 70°
Angle ABC is the linear pair with 120°, so the size is 180-120-60°
Angle A corresponds to angle 60°, so they are equal
Angle BAC is the linear pair with angle A and angle 70°, so 180-(60+70)=50°
Angle ACB is 180-(50+60) = 70°