Lets say angle ABD is Y. We know angle BDC is 2x and that angles ABD + BAD = 2x since angle BDA is 180-DBC(2x) and so Y+X = 2x so we can figure out Y =X. With equal angles AD=BD. and in turn BD=BC
2. INSUFF since we might figure out the property like 1 but no known length to work with.
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