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            • 1.

              在长方体\(ABCD—A_{1}B_{1}C_{1}D_{1}\)中,对角线\(B_{1}D\)与平面\(A_{1}BC_{1}\)相交于点\(E\),则点\(E\)为\(\triangle A_{1}BC_{1}\)的(    )

              A.垂心
              B.重心
              C.外心
              D.内心
            • 2.

              如下图,\(PA\)是圆\(O\)的切线,切点为\(A,PO\)交圆\(O\)于两点,\(PA=\sqrt{3},PB=1\),则\(AC=\)          

            • 3. 如图,\(\triangle ABC\)中,边\(AC\)上一点\(F\)分\(AC\)为\( \dfrac {AF}{FC}= \dfrac {2}{3}\),\(BF\)上一点\(G\)分\(BF\)为\( \dfrac {BG}{GF}= \dfrac {3}{2}\),\(AG\)的延长线与\(BC\)交于点\(E\),则\(BE\):\(EC=\) ______ .
            • 4. 如图,平行四边形\(ABCD\)中,\(AE\):\(EB=1\):\(2\),若\(\triangle AEF\)的面积等于\(2cm^{2}\),则\(\triangle CDF\)的面积等于\((\)  \()\) 
              A.\(16\) \(cm^{2}\)
              B.\(18\) \(cm^{2}\)
              C.\(20\) \(cm^{2}\)
              D.\(22\) \(cm^{2}\)
            • 5. 如图所示,已知\(PA\)与\(⊙O\)相切,\(A\)为切点,\(PBC\)为割线,弦\(CD/\!/AP\),\(AD\)、\(BC\)相交于\(E\)点,\(F\)为\(CE\)上一点,且\(∠EDF=∠ECD\).
              \((1)\)求证:\(\triangle DEF\)∽\(\triangle PEA\);
              \((2)\)若\(EB=DE=6\),\(EF=4\),求\(PA\)的长.
            • 6. 如图,已知\(⊙A\)和\(⊙B\)的公共弦\(CD\)与\(AB\)相交于点\(E\),\(CB\)与\(⊙A\)相切,\(⊙B\)半径为\(2\),\(AE=3\).
              \((\)Ⅰ\()\)求弦\(CD\)的长;
              \((\)Ⅱ\()⊙B\)与线段\(AB\)相交于点\(F\),延长\(CF\)与\(⊙A\)相交于点\(G\),求\(CG\)的长.
            • 7. 如图,在锐角三角形\(ABC\)中,\(D\)为\(C\)在\(AB\)上的射影,\(E\)为\(D\)在\(BC\)上的射影,\(F\)为\(DE\)上一点,且满足\( \dfrac {EF}{FD}= \dfrac {AD}{DB}\).
              \((\)Ⅰ\()\)证明:\(CF⊥AE\);
              \((\)Ⅱ\()\)若\(AD=2\),\(CD=3.DB=4\),求\(\tan ∠BAE\)的值.
            • 8. 如图,已知圆\(O\)外有一点\(P\),作圆\(O\)的切线\(PM\),\(M\)为切点,过\(PM\)的中点\(N\),作割线\(NAB\),交圆于\(A\)、\(B\)两点,连接\(PA\)并延长,交圆\(O\)于点\(C\),连续\(PB\)交圆\(O\)于点\(D\),若\(MC=BC\).
              \((1)\)求证:\(\triangle APM\)∽\(\triangle ABP\);
              \((2)\)求证:四边形\(PMCD\)是平行四边形.
            • 9.
              选修\(4—1\):几何证明选讲

              如图,\(AE\)是圆\(O\)的切线,\(A\)是切点,\(AD⊥OE\)于\(D\),割线\(EC\)交圆\(O\)于\(B\)、\(C\)两点.

              \((1)\)证明:\(O\)、\(D\)、\(B\)、\(C\)四点共圆;

              \((2)\)设\(∠DBC=50^{\circ}\),\(∠ODC=30^{\circ}\),求\(∠OEC\)的大小.

            • 10.
              \(\triangle ABC\)中,\(∠BAC=45^{\circ}\),\(AD⊥BC\)于\(D\),\(BD=2\),\(DC=3\),则\(AD\)的长为 ______ .
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