27.已知:點(diǎn)A的坐標(biāo)是(6,0),點(diǎn)B、點(diǎn)C分別在y軸負(fù)半軸和正半軸上,連接CA,過點(diǎn)B作BD⊥AC,垂足為點(diǎn)D,BD交OA于點(diǎn)E,且CA=BE.
(1)如圖1,求點(diǎn)B的坐標(biāo);
(2)如圖2,點(diǎn)H在線段AB上,連接CH、OH,設(shè)C的縱坐標(biāo)為t,△COH的面積為S,若CA=CH,求S與t的關(guān)系式;
(3)如圖3,在(2)的條件下,連接OD并延長(zhǎng)至點(diǎn)F,使OF=OH,連接FH交OA于點(diǎn)G,若HG=2FG,∠HCA=2∠BOH,求t的值.