Geometry Problems, Online Education

Problem 91. Similar Triangles, Altitude, Parallel, Perpendicular. Level: High School, College

In the figure below, given a triangle ABC, an altitude AH = h, line DEF parallel to AC and line FGM parallel to AB. If h1, h2, and h3 are perpendicular to BC respectively, prove that: h = h1 + h2 + h3.

Similarity of triangles 


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

 

 

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