Gogeometry Problem 217 dans Euclide Geometry Problem par Harvey Littleman From Gogeometry Using : Isometric transformation Additional points congruent triangles Define J in FG such as JG ⊥ JB => JB=GD ED//BF => ∠JBF=∠HDE In ΔHDE, ∠HDE + ∠DEH =90° => in ΔJBF, ∠JBF + ∠BFJ =90° =>∠JFB = ∠HED FB=DE => ΔJBF is congruent to ΔHDE (AAA) => JB=HD =>GD=HD Therefore a=b
