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Problem 4.
Triangle, Quadrilateral, Angles, 120 Degrees. Level: High School, SAT Prep, College
geometry |
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In the figure, AD = CD = BC, and angle
C = 2(angle
A). Prove that x = 120° - angle
A. See also Problem 42.
Post
a comment or solution. Try to use elementary geometry (Euclid's Elements.)
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Hints:
Key theorems
Triangle congruence
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