共50条信息
如图,\(PC\)与圆\(O\)相切于点\(C\),直线\(PO\)交圆\(O\)于\(A\),\(B\)两点,弦\(CD\)垂直\(AB\)于\(E.\)则下面结论中正确的有( )个
\(①ABEC\)∽\(\triangle DEA②∠ACE=∠ACP\)
\(③DE^{2}=OE·EP④PC^{2}=PA·AB\)
如图,\(⊙O\)的半径为\(6\),线段\(AB\)与\(⊙O\)相较于\(C\)、\(D\)两点,\(OB\)与\(⊙O\)相交于点\(E\),\(AC=4\),\(CD=3\),\(∠BOD=∠A\),则\(BE=\)( )
直角三角形\(ABC\)中,三内角成等差数列,最短边的长度为\(1{,}P\)为\({\triangle }ABC\)内的一点,且\({∠}APB{=}{∠}APC{=}{∠}CPB{=}120^{{∘}}\),则\(PA+PB+PC=\)
如图,已知\(PA\)和圆\(O\)相切,切点为\(A\),\(PBC\)为割线,\(D\)是圆\(O\)上一点,\(AD\),\(BC\)相交于点\(E.\)若\(F\)为\(CE\)上一点使得\(∠EDF=∠P\),已知\(EF=2\),\(EB=4\),\(PB=8\),则\(PA\)的长为( )
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