72529
The equation given by Fuss ' theorem , giving the relation among the radius of a bicentric quadrilateral 's inscribed circle , the radius of its circumscribed circle , and the distance between the centers of those circles , can be expressed as a quadratic equation for which the distance between the two circles ' centers in terms of their radii is one of the solutions .
 Fuss
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Fuss