Question 195952
in  a  plane
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locus  equidistant  from  A  and  B,  is  a  line perpendicular  to  AB,  at  midpoint  of  AB
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TWO  POINTS  are  on  this  perpendicular  line,  4 "  from  AB 
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in  a  3  dim  situation
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loci  between  A  and  B,  is  a  perpendicular  plane to  AB,  at  midpoint
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the  loci  4"  from  AB  in  the  plane  is  a  circle  of  4""  radius, center  at  midpoint  AB
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