共50条信息
在\(\triangle ABC\)中,已知\(∠B=∠C\),则( )
如图,\(\triangle ABC\)和\(\triangle ECD\)都是等腰直角三角形,\(CA=CB\),\(CE=CD\),\(\triangle ACB\)的顶点\(A\)在\(ECD\)的斜边\(DE\)上,求证:\(AE^{2}+AD^{2}=2AC^{2}\).
\((2)\)若四边形\(EBFD\)是菱形,求\(∠ABD\)的度数.
在\(□\)\(ABCD\)中,过点\(D\)作\(DE\)\(⊥\)\(AB\)于点\(E\),点\(F\)在边\(CD\)上,\(DF\)\(=\)\(BE\),连接\(AF\),\(BF\).
\(⑴\)求证:四边形\(BFDE\)是矩形;
\(⑵\)若\(CF\)\(=3\),\(BF\)\(=4\),\(DF\)\(=5\),求证:\(AF\)平分\(∠\)\(DAB\).
如图,\(\triangle ABC\)中,\(∠A=36^{\circ}\),\(AB=AC\),\(CD\)平分\(∠ACB\),试说明\(\triangle BCD\)是等腰三角形.
如图,在\(\triangle ABC\)中,\(∠ABC\)与\(∠ACB\)的平分线相交于点\(D\),过点\(D\)作\(EF/\!/BC\),分别交\(AB\)、\(AC\)于点\(E\)、\(F\),若\(AB=5\),\(AC=6\),则\(\triangle AEF\)的周长是_____.
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