Problem 89. Triangle area, Midpoints. Level: High School, SAT Prep, College

In the figure below, given a triangle AED, M and N are the midpoints of cevians AC and DB respectively. If S1, S2, and S3 are the areas of the triangles EBM, ECN, and BEC respectively, prove that: Equal triangle area conclusion. Post a comment.

Problem about triangle area and midpoints 

 

 

 

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. CEVIAN: A cevian is a line segment which joins a vertex of a triangle with a point on the opposite side (or its extension).


2. AREA OF A TRIANGLE:

Proposition: The area of a triangle equals one-half the product of the length of a side and the length of the altitude to that side.

Triangle area base, altitude 

 


3. Mid-Segment or Midline of a Triangle Theorem: If a line MN joins the midpoints of two sides of a triangle, then it is parallel to the third side and its length is one-half the length of the third side.

Mid Segment or Midline theorem


 

Math problem about equal area

 

 

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Last updated: May 22, 2009