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| Question 1010983:  find the equation of circle passing through the points of intersection of the lines x + 3y=0 and 2x- 7y = 0 and whose center is point of intersection lines x + y +1=0 and x-2y +4=0
 Answer by MathLover1(20850)
      (Show Source): 
You can put this solution on YOUR website!  find the equation of circle passing through the points of intersection of the lines 
  
   --------------find intersection point
 
  
  substitute in
 
   
   
   
  
   =>
   intersection point is at (
  ,  ) 
 and whose center is point of intersection lines
 
   
   ----------------------------subtract
 
  
   
   
  
   then
  =>  =>   so, if the center of the circle is at (
  ,  ) =(  ,  ) and circle passes through  (  ,  ) , its radius will be the distance between these two points 
 
 
 | Solved by pluggable solver: Distance Formula |  | 
 The first point is (x1,y1). The second point is (x2,y2)
 
 
 Since the first point is (0, 0), we can say (x1, y1) = (0, 0)
 So
  ,  
 
 Since the second point is (-2, 1), we can also say (x2, y2) = (-2, 1)
 So
  ,  
 
 Put this all together to get:
  ,  ,  , and  
 --------------------------------------------------------------------------------------------
 
 
 Now use the distance formula to find the distance between the two points (0, 0) and (-2, 1)
 
 
 
 
  
 
 
  Plug in  ,  ,  , and  
 
 
  
 
 
  
 
 
  
 
 
  
 
 
  
 ==========================================================
 
 Answer:
 
 
 The distance between the two points (0, 0) and (-2, 1) is exactly
  units 
 
 The approximate distance between the two points is about 2.23606797749979 units
 
 
 
 So again,
 
 
 Exact Distance:
  units 
 
 Approximate Distance:
  units 
 
 
 |  
 so, we have
  ,  and  and the equation of your circle is: 
   
   
 
 
   
 
 
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