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| Question 1040743:  Find the equation of the circle when a triangle whose sides lie on the lines 3x+4y=-8, 3x-4y=32, and x-8=0 inscribed the circle.
 Answer by Fombitz(32388)
      (Show Source): 
You can put this solution on YOUR website! Find the intersection points. From eq. 3,
 
  Substituting into eq. 1,
 
  
  
  
  (8,-8)
 Substituting into eq. 2,
 
  
  
  
  (8,-2)
 Finally adding eq. 1 and eq. 2,
 
  
  
  So,
 
  
  
  
  (4,-5)
 Now you have three points on the circle, solve for the circle.
 Use the general form,
 
  .
 .
 (8,-8):
 
  
  4.
  .
 .
 (8,-2):
 
  
  5.
  .
 .
 (4,-5):
 
  
  6.
  Subtracting eq. 5 from eq. 4,
 
  
  
  Substituting into eq. 4,
 
  7.
  Substituting into eq. 6,
 
  8.
  Now subtracting eq. 8 from eq. 7,
 
  
  
  Substituting into eq. 8,
 
  
  
   .
 .
 
  You can complete the square to get into center-radius form,
 
  
  
  
  
  Center : (
  ,  ) Radius :
  .
 .
 .
 
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