Geometry Problem 1372: Equilateral Triangle, Exterior Cevian, Inradius, Exradius, Altitude, Sketch, iPad Apps.

Proposition

In the figure below, ABC is an equilateral triangle with altitude h. D is a point on CA extended, r1 is the inradius of the triangle DAB and r2 is the exradius of the triangle DBC corresponding to BC. Prove that r1 + r2 = h.

BD is called an exterior cevian of triangle ABC
 
 

Geometry Problem 1372: Equilateral Triangle, Exterior Cevian, Inradius, Exradius, Altitude, Sketch, iPad Apps
 
 

Sketch and Typography of problem 1372 using iPad Apps


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