共50条信息
\((1)\)求\(C\)和\(BD;\)
\((2)\)求四边形\(ABCD\)的面积.
在如图所示的几何体中,四边形\(DCEF\)为正方形,四边形\(ABCD\)为等腰梯形,\(AB/\!/CD,AC=\sqrt{3},AB=2BC=2\),且\(AC\bot FB\).
\((\)Ⅰ\()\)求证:平面\(EAC\bot \)平面\(FCB\);
\((\)Ⅱ\()\)若线段\(AC\)上存在点\(M\),使\(AE/\!/\)平面\(FDM\),求\(\dfrac{AM}{MC}\)的值.
如图,在空间四边形\(ABCD\)中,\(E\),\(F\)分别是\(AB\),\(AD\)的中点,\(G\),\(H\)分别在\(BC\),\(CD\)上,且\(BG:GC=DH:HC=1:2\).
\((1)\)求证:\(E\),\(F\),\(G\),\(H\)四点共面;
\((2)\)设\(EG\)与\(HF\)交于点\(P\),求证:\(P\),\(A\),\(C\)三点共线.
进入组卷