Answer:
the answer is 5
Step-by-step explanation:
wait what is ur question
Angle 1 = 39, Angle 2 = 78 , Angle 3 = 63
78/2 = 39
(Angle 2/2 = Angle 1)
78 - 15 = 63
(Angle 2 - 15 = Angle 3)
39 + 78 + 63 = 180
(Angle 1 + Angle 2 + Angle 3 = 180)