20.在正方形網(wǎng)格中建立如圖所示的平面直角坐標(biāo)系xOy,△ABC的三個(gè)頂點(diǎn)都在格點(diǎn)上,A的坐標(biāo)是(4,4),請(qǐng)回答下列問(wèn)題:
(1)將△ABC向下平移六個(gè)單位長(zhǎng)度,畫(huà)出平移后的△A
1B
1C
1,并寫(xiě)出點(diǎn)A的對(duì)應(yīng)點(diǎn)A
1的坐標(biāo);
(2)畫(huà)出△ABC關(guān)于原點(diǎn)O對(duì)稱的△A
2B
2C
2,并寫(xiě)出點(diǎn)A
2的坐標(biāo);
(3)判斷△A
1B
1C
1與△A
2B
2C
2是否關(guān)于某點(diǎn)成中心對(duì)稱;若是,請(qǐng)畫(huà)出對(duì)稱中心M,并寫(xiě)出點(diǎn)M的坐標(biāo)