Answer:
66
Step-by-step explanation:
Angle 2 and 4 are supplementary, so if angle 4 is 123, then 180-123=57.
So angle 2 is 57.
Then, if angle 2 and 3 are 57 and we know that all angles of a triangle have to add up to 180, then:
57+57+angle 1=180
114+ angle 1=180
angle 1= 66
