Machu Picchu. Math teacher Master Degree.

 Problem 117. Area of Triangles, Incenter, Excircles. Level: High School, SAT Prep, College

In the figure below, given a triangle ABC, construct the incenter I and the excircles with excenters P and Q. Let be D and E the tangent points of triangle ABC with its excircles. IE and BC meet at H, and ID and AB meet at G. If S1, S2, S3, and S4 are the areas of the triangles AIG, BEH, BDG, and CHI respectively, prove that S1 + S2 = S3 + S4. Post a comment or solution.

Elearning 117: triangle area, incenter, excenters 

 

 

FACTS AND HINTS:

Geometry problem solving is one of the most challenging skills for students to learn. When a problem requires auxiliary construction, the difficulty of the problem increases drastically, perhaps because deciding which construction to make is an ill-structured problem. By “construction,” we mean adding geometric figures (points, lines, planes) to a problem figure that wasn’t mentioned as "given."


 

 

Problem Triangle area, incenter, excircles

 

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