共50条信息
如图,\(AB\)为\(⊙O\)的直径,\(C\),\(D\)为\(⊙O\)上的两点,若\(AB=14\),\(BC=7.\)则\(∠BDC\)的度数是
如图,在\(Rt\triangle ABC\)中,\(∠ACB =90^{\circ}\),\(∠ABC=30^{\circ}\),将\(\triangle ABC\)绕点\(C\)顺时针旋转\(\alpha \)角\((0^{\circ} < \)\(\alpha \)\( < 180^{\circ})\)至\(\triangle A′B′C\),使得点\(A′\)恰好落在\(AB\)边上,则\(\alpha \)等于\((\) \()\).
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