Answer: I could be wrong but it's probably 3.
Step-by-step explanation: Once there's x in the 3 sides of angles you subtract. 73 minus 3 = 3 degrees. If I'm wrong sorry about that. I will try to improve. :)
Answer:
37°
Step-by-step explanation:
70°+73°+x°=180°
143°+x°=180°
x°=180°-143°
x°=37°
