Respuesta :

Answer:

in every question you should subtract the given value by 180

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Basic fact:

angles on a straight line always add up to 180 degrees

Step-by-step explanation:

  1. 39+a=180       a=141
  2. 157+a=180      a=23
  3. 92+a=180       a=88
  4. 60+a=180       a=120
  5. 61+a=180        a=119
  6. 28+a=180       a=152
  7. 52+a=180       a=128
  8. 121+a=180       a=59
  9. 151+a=180       a=29
  10. 128+a=180      a=52