共50条信息
如图,双曲线\(y=\dfrac{2}{x}(x > 0)\)经过四边形\(OABC\)的顶点\(A\)、\(C\),\(∠ABC=90^{\circ}\),\(OC\)平分\(OA\)与\(x\)轴正半轴的夹角,\(AB/\!/x\)轴,将\(\triangle ABC\)沿\(AC\)翻折后得到\(\triangle AB′C\),\(B′\)点落在\(OA\)上,则四边形\(OABC\)的面积是\((\) \()\)
如图,在\(\triangle ABC\)中,\(AD\)为\(∠BAC\)的平分线,\(DE⊥AB\)于\(E\),\(DF⊥AC\)于\(F\).
\((1)\)若\(\triangle ABC\)面积是\(40 cm^{2}\),\(AB=12 cm\),\(AC=8 cm\),求\(DE\)的长;
\((2)\)求证:\(S_{\triangle ABD}∶S_{\triangle ACD}=AB∶AC\).
求证:\((1)∠ECD=∠EDC\) ;\((2)OE\)是\(CD\)的垂直平分线.
如图,四边形\(ABCD\)是正方形,\(M\)是\(BC\)边上的一点,\(E\)是\(CD\)边的中点,\(AE\)平分\(∠DAM\).
\((1)\)求证\(AM=AD+MC\);
\((2)\)若\(AD=4\),求\(AM\)的长.
如图,\(DA⊥AC\),\(DE⊥BC\),若\(AD=5 cm\),\(DE=5 cm\),\(∠ACD=30^{\circ}\),则\(∠DCE\)为( )
\((1)\)如图\(1\),若点\(O\)在\(BC\)上,求证:\(AB=AC\);
\((2)\)如图\(2\),若点\(O\)在\(\triangle ABC\)内部,求证:\(AB=AC\);
\((3)\)猜想,若点\(O\)在\(\triangle ABC\)的外部,\(AB=AC\)成立吗?请说明理由.
\((2)\)若\(∠B=30^{\circ}\),\(CD=1\),求\(BD\)的长.
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