《證明三》復(fù)習(xí)課

1、平行四邊平行四邊形形矩形矩形 菱形菱形正方形正方形等腰梯形等腰梯形對(duì)邊平行且相等對(duì)邊平行且相等對(duì)角相等對(duì)角相等對(duì)角線互相平分對(duì)角線互相平分四條邊相等四條邊相等四個(gè)角相等四個(gè)角相等對(duì)角線互相垂直對(duì)角線互相垂直對(duì)角線相等對(duì)角線相等對(duì)角線平分對(duì)角線平分一組對(duì)角一組對(duì)角軸對(duì)稱(chēng)圖形軸對(duì)稱(chēng)圖形中心對(duì)稱(chēng)圖形中心對(duì)稱(chēng)圖形圖形圖形 性質(zhì)性質(zhì) 對(duì)邊平行相等對(duì)邊平行相等對(duì)角相等對(duì)角相等對(duì)角線平分對(duì)角線平分四個(gè)直角四個(gè)直角對(duì)角線相等對(duì)角線相等四邊相等四邊相等對(duì)角線互相對(duì)角線互相垂直且平分垂直且平分對(duì)角對(duì)角兩組對(duì)邊平行兩組對(duì)邊平行兩組對(duì)邊相等兩組對(duì)邊相等兩組對(duì)角相等兩組對(duì)角相等一組對(duì)邊平行且相等一組對(duì)邊平行且相等有一個(gè)

2、角有一個(gè)角是直角是直角對(duì)角線相等對(duì)角線相等有一組鄰有一組鄰邊相等邊相等對(duì)角線互對(duì)角線互相垂直相垂直對(duì)角線對(duì)角線相等相等對(duì)角線互對(duì)角線互相垂直相垂直有一組鄰有一組鄰邊相等邊相等有一個(gè)角有一個(gè)角是直角是直角四個(gè)角是直角四個(gè)角是直角四條邊都相等四條邊都相等對(duì)角線互相平分對(duì)角線互相平分ABC.D問(wèn)題問(wèn)題1 1：如何在邊如何在邊ABAB、ACAC上上分別取點(diǎn)分別取點(diǎn)E E、F F，使四邊形，使四邊形AEDFAEDF是平行四邊形？是平行四邊形？問(wèn)題問(wèn)題2 2：如圖如圖, ,四邊形四邊形AEDFAEDF是平是平行四邊形行四邊形 ，若，若ADAD是角平分線，是角平分線，則四邊形則四邊形AEDFAEDF是是_菱形菱形（一）如圖如圖,D,D是是ABCABC邊邊BCBC上上任意一點(diǎn)。任意一點(diǎn)。FE圖11 2 3 CABFDE圖2問(wèn)題問(wèn)題3 3：如圖如圖, ,四邊形四邊形AEDFAEDF是平行四邊形是平行四邊形 ，若，若BACBAC是直角時(shí)，四邊形是直角時(shí)，四邊形AEDFAEDF是是_問(wèn)題問(wèn)題4 4：四邊形四邊形AEDFAEDF是平行四邊形是平行四邊形 ，若若ADAD是角平分線且是角平分線且BACBAC是直角時(shí)，是直角時(shí)，四邊形四邊形AEDFAEDF是是_矩形矩形正方形正方形（一）如圖如圖,D,D是是ABC