Respuesta :

MathPhys

Answer:

40°

Step-by-step explanation:

Supplementary angles add up to 180°.  Complementary angles add up to 90°.

m∠1 + m∠2 = 180°

115° + m∠2 = 180°

m∠2 = 65°

m∠2 + m∠3 = 90°

65° + m∠3 = 90°

m∠3 = 25°

m∠2 − m∠3 = 65° − 25° = 40°