如图,平面直角坐标系中,将线段\(AB\)平移,使点\(A(0,3)\)平移到\(A′(5,0)\),\(B\)平移到\(B′(1,-3)\)
\((1)\)则\(B\)点的坐标为________;
\((2)\)求\(\triangle AB′B\)的面积:
\((3)A′B′\)的延长线交\(y\)轴于\(C\),点\(D\)、\(E\)分别是\(x\)轴、射线\(A′B′\)上的点\(.\)若\(∠ABD\)的平分线\(BF\)的反向延长线交\(CE\)于点\(H\),\(∠ECO\)的平分线交\(BH\)于点\(G\),求\(∠HGC\)的度数.