Respuesta :

Answer:

m∠1 = 123°

Step-by-step explanation:

Since a straight line is always a supplementary angle, it equals 180°. To solve for the unknown angle, we can subtract the known angle from 180°.

180° - 57° = 123°

So m∠1 = 123°

dn112

180-57= 123 is the measurement for angle 2

All straight line is equal to 180