GivenanondegenerateconicC,proveBrianchon’stheorem:Foranyhexagon(a,b,c,d,e,f)circumscribedaboutC(whichmeansthat〈a,b〉,〈b,c〉,〈c,d〉,〈d,e〉,〈e,f〉,and〈f,a〉aretangenttoC),thediagonals〈a,d〉,〈b,e〉,and〈c,f〉areco...

GivenanondegenerateconicC,proveBrianchon’stheorem:Foranyhexagon(a,b,c,d,e,f)circumscribedaboutC(whichmeansthat〈a,b〉,〈b,c〉,〈c,d〉,〈d,e〉,〈e,f〉,and〈f,a〉aretangenttoC),thediagonals〈a,d〉,〈b,e〉,and〈c,f〉areconcur-rent.