Problem 95. Similar Triangles, Inradii, Parallel. Level: High School, SAT Prep, College

In the figure below, given a triangle ABC, line DEF parallel to AC and line FGM parallel to AB. If r, r1, r2, and r3, are the inradii of triangles ABC, DBE, FGE, and MGC respectively, prove that: r = r1 + r2 + r3. Post a comment.

Problem 95 Similarity, Elearning

 

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."


1. SIMILAR TRIANGLES:
Proposition:
Corresponding segments of similar triangles are in proportion.


 

Similarity Problem 95, Elearning

 

 

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