Let ABC be a triangle, D a point on BC and r, r_b, r_c the inradii of ABC, ABD, ACD, resp. 1. AB _|_ BC ( ie A = 90 d.), AD _|_ BC (ie AD is the a-altitude) ==> r^2 = r_b^2 + r_c^2
(Old theorem)
2. ΨΗΦ. Πρόβλημα 19
Κυριακή 15 Οκτωβρίου 2023
INRADII PROBLEM
Let ABC be a triangle, D a point on BC and r, r_b, r_c the inradii of ABC, ABD, ACD, resp. 1. AB _|_ BC ( ie A = 90 d.), AD _|_ BC (ie AD is the a-altitude) ==> r^2 = r_b^2 + r_c^2
(Old theorem)
2. ΨΗΦ. Πρόβλημα 19
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Let ABC be a triangle. Denote: (N1),(N2), (N3) = the NPCs of IBC, ICA, IAB, resp. (12), (13) = the reflections of (N1) in BI, CI, resp. ... -
Theorem 1. Let ABC be an equilateral triangle and P a point. The Euler lines of the triangles PBC,PCA,PAB are concurent.Denote the point ...
