24.已知點(diǎn)C是∠MAN平分線上一點(diǎn),∠BCD的兩邊CB、CD分別與射線AM、AN相交于B,D兩點(diǎn),且∠ABC+∠ADC=180°.過點(diǎn)C作CE⊥AB,垂足為E.
(1)如圖1,當(dāng)點(diǎn)E在線段AB上時(shí),求證:BC=DC;
(2)如圖2,當(dāng)點(diǎn)E在線段AB的延長線上時(shí),探究線段AB、AD與BE之間的等量關(guān)系;
(3)如圖3,在(2)的條件下,若∠MAN=60°,連接BD,作∠ABD的平分線BF交AD于點(diǎn)F,交AC于點(diǎn)O,連接DO并延長交AB于點(diǎn)G.若BG=1,DF=2,求線段DB的長.