<PRE><B>Question 328067</B>
The exterior angle theorem is a theorem in elementary geometry which states that the exterior angle of a triangle is equal to the sum of the two remote interior angles.

 

Since angle z is the exterior angle, we have the folowing equation:  z = x + y.

  

170 - n = 6n - 20 + 4n + 47 

  

170 - n = 10n + 27 

  

170 - 27 = 10n + n 

  

143 = 11n 

  

143/11 = n 

  

13 = n 

  

z = 170 - n 

  

z = 170 - 13 

  

z = 157 

  
The answer is choice B. 

  

  

  

  

  

  

  

  

  

 

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