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<EDC = 2< BCD = 2< CAB, 100-60-20 (2023 Novosibirsk Oral Geo Oly 9.7)

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September 5, 2023
anglesgeometry

Problem Statement

Triangle ABCABC is given with angles ∠ABC=60o\angle ABC = 60^o and ∠BCA=100o\angle BCA = 100^o. On the sides AB and AC, the points DD and EE are chosen, respectively, in such a way that ∠EDC=2∠BCD=2∠CAB\angle EDC = 2\angle BCD = 2\angle CAB. Find the angle ∠BED\angle BED.
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