Respuesta :
Answer:
57
Step-by-step explanation:
since angle 3 is 57 (180-123=57) and 3 and 7 are corresponding, and corresponding angles are congruent,angle 7=57
Answer:
angle 1 and angle 7=180°[co exterior angle]
123°+ <7=180°
<7=180°-123°
<7=57°