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 Problem 111. Orthogonal Circles. Level: High School, SAT Prep, College

In the figure below, given a circle of center O and diameter AB, AC and BD meet at E. If F is the circumcenter of triangle DEC, prove that:  angle OCF = 90º.
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Orthogonal circles, 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."


 

 

Problem 111: Orthogonal Circles. Elearning.

 

 

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