Monday, February 22, 2021

1664. Congruent Circles

2 comments:

  1. The square of the radius of the congruent circles is r^2 (R-2 r) /(9 R).

    Barycentric equation of the circle (HaHbcHcb) is:

    a^6 x^2-3 a^4 b^2 x^2+3 a^2 b^4 x^2-b^6 x^2-6 a^4 b c x^2+6 a^3 b^2 c x^2+6 a^2 b^3 c x^2-6 a b^4 c x^2-3 a^4 c^2 x^2+6 a^3 b c^2 x^2+2 a^2 b^2 c^2 x^2-6 a b^3 c^2 x^2+b^4 c^2 x^2+6 a^2 b c^3 x^2-6 a b^2 c^3 x^2+3 a^2 c^4 x^2-6 a b c^4 x^2+b^2 c^4 x^2-c^6 x^2+2 a^6 x y-6 a^4 b^2 x y+6 a^2 b^4 x y-2 b^6 x y+4 a^5 c x y-12 a^4 b c x y+4 a^3 b^2 c x y+12 a^2 b^3 c x y-8 a b^4 c x y-4 a^4 c^2 x y+4 b^4 c^2 x y-8 a^3 c^3 x y+12 a^2 b c^3 x y+4 a b^2 c^3 x y+2 a^2 c^4 x y-2 b^2 c^4 x y+4 a c^5 x y+a^6 y^2-3 a^4 b^2 y^2+3 a^2 b^4 y^2-b^6 y^2+4 a^5 c y^2-6 a^4 b c y^2-2 a^3 b^2 c y^2+6 a^2 b^3 c y^2-2 a b^4 c y^2-a^4 c^2 y^2-6 a^3 b c^2 y^2-2 a^2 b^2 c^2 y^2+6 a b^3 c^2 y^2+3 b^4 c^2 y^2-8 a^3 c^3 y^2-6 a^2 b c^3 y^2-2 a b^2 c^3 y^2-a^2 c^4 y^2-6 a b c^4 y^2-3 b^2 c^4 y^2+4 a c^5 y^2+c^6 y^2+2 a^6 x z+4 a^5 b x z-4 a^4 b^2 x z-8 a^3 b^3 x z+2 a^2 b^4 x z+4 a b^5 x z-12 a^4 b c x z+12 a^2 b^3 c x z-6 a^4 c^2 x z+4 a^3 b c^2 x z+4 a b^3 c^2 x z-2 b^4 c^2 x z+12 a^2 b c^3 x z+6 a^2 c^4 x z-8 a b c^4 x z+4 b^2 c^4 x z-2 c^6 x z+2 a^6 y z+4 a^5 b y z-4 a^4 b^2 y z-8 a^3 b^3 y z+2 a^2 b^4 y z+4 a b^5 y z+4 a^5 c y z+4 a^3 b^2 c y z-8 a b^4 c y z-4 a^4 c^2 y z+4 a^3 b c^2 y z-4 a^2 b^2 c^2 y z+4 a b^3 c^2 y z-8 a^3 c^3 y z+4 a b^2 c^3 y z+2 a^2 c^4 y z-8 a b c^4 y z+4 a c^5 y z+a^6 z^2+4 a^5 b z^2-a^4 b^2 z^2-8 a^3 b^3 z^2-a^2 b^4 z^2+4 a b^5 z^2+b^6 z^2-6 a^4 b c z^2-6 a^3 b^2 c z^2-6 a^2 b^3 c z^2-6 a b^4 c z^2-3 a^4 c^2 z^2-2 a^3 b c^2 z^2-2 a^2 b^2 c^2 z^2-2 a b^3 c^2 z^2-3 b^4 c^2 z^2+6 a^2 b c^3 z^2+6 a b^2 c^3 z^2+3 a^2 c^4 z^2-2 a b c^4 z^2+3 b^2 c^4 z^2-c^6 z^2=0.
    Angel Montesdeoca, 23.02.2021

    ReplyDelete
  2. Instead of orthocenters, we can use Fermat points. Congruence of circles hold.

    ReplyDelete

1987. Circumcenter On Euler Line

 Let H=X(4)-Orthocenter of ABC. A 1 B 1 C 1 cevian triangle of H. B1 A , C1 A are reflections of B1, C1 on A. L A , line through B1 A , C1...