Respuesta :
Answer:
180-45=135
Step-by-step explanation:
The unknown angle can be found by subtracting 180-45=135. ABC measures 180 because it is a straight angel and ABC meausres 45.
since ABC is a straight angle, it measures 180°. since you have 45° already, you can input it into an equation.
45 + x = 180
or
180 - 45 = x
45 + x = 180
or
180 - 45 = x