Problem 420. Triangle, Angles, Altitude, Sides, Measurement.
Level: High School, College, SAT Prep.
The figure shows a triangle ABC with
BC = 3AB, altitude BD, angle DBC = 3 angle ABD, and AD = 1. Find
CD.
Geometry problem solving
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 illstructured problem. By “construction,” we mean adding geometric figures (points, lines, planes) to a problem figure that wasn’t mentioned as "given."

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