【導(dǎo)讀】若是請(qǐng)畫(huà)出它的對(duì)稱(chēng)軸.它是軸對(duì)稱(chēng)圖形嗎?運(yùn)動(dòng)與自身重合呢?旋轉(zhuǎn)中心,把三角形逆時(shí)針旋轉(zhuǎn)180°,作出所得的像.如圖2,點(diǎn)O是平行四邊形ABCD對(duì)角線AC、BD的交點(diǎn),于點(diǎn)O成中心對(duì)稱(chēng).1)A點(diǎn)關(guān)于O點(diǎn)的對(duì)稱(chēng)點(diǎn)是;線AC、BD交于O點(diǎn)。3)線段AD關(guān)于O點(diǎn)的對(duì)稱(chēng)線段是;連結(jié)AO并延長(zhǎng)到A’,使OA’=OA,