\((1)\)已知\(a=(2,-1,3)\)、\(b=(-1,4,-2)\)、\(c=(7,7,λ)\),若\(a\)、\(b\)、\(c\)共面,则实数\(λ=\)________.
\((2)\)定点\(P\)不在\(\Delta ABC\)所在的平面内,过\(P\)作平面\(\alpha \),使\(\Delta ABC\)的三个顶点到\(\alpha \)的距离相等,这样的平面共有__________个.
\((3)\)已知正三棱锥\(V-ABC\)的正视图、侧视图和俯视图如图所示\(.\)则侧视图的面积是________.
\((4)\)如图,在正方体\(ABCD-{{A}_{1}}{{B}_{1}}{{C}_{1}}{{D}_{1}}\)中,棱长为\(1\) ,点\(P\)为线段\({{A}_{1}}C\)上的动点\((\)包含线段端点\()\),则下列结论正确的______.
\(①\)当\( \overset{⇀}{{A}_{1}C}= \overset{⇀}{3{A}_{1}P} \)时, \({{D}_{1}}P/\!/\)平面\(BD{{C}_{1}}\); \(②\)当\( \overset{⇀}{{A}_{1}C}= \overset{⇀}{3{A}_{1}P} \)时, \({{A}_{1}}C\bot \)平面\({{D}_{1}}AP\); \(③\)\(\angle AP{{D}_{1}}\)的最大值为\({{90}^{\circ }}\); \(④\)\(AP+P{{D}_{1}}\)的最小值为\(\dfrac{2\sqrt{6}}{3}\).