Question

圓有________條對(duì)稱(chēng)軸；扇形有________條對(duì)稱(chēng)軸；長(zhǎng)方形有________對(duì)稱(chēng)軸；正方形有________對(duì)稱(chēng)軸．．

Answer 1

無(wú)數(shù)    1    2    4
分析：根據(jù)對(duì)稱(chēng)軸的定義可知，如果沿某條直線(xiàn)對(duì)折，對(duì)折的兩部分是完全重合的，那么就稱(chēng)這樣的圖形為軸對(duì)稱(chēng)圖形，這條直線(xiàn)叫做這個(gè)圖形的對(duì)稱(chēng)軸；由此可以確定上題中對(duì)稱(chēng)軸的條數(shù)．
解答：根據(jù)軸對(duì)稱(chēng)圖形的定義可知：圓有無(wú)數(shù)條對(duì)稱(chēng)軸；扇形有1條對(duì)稱(chēng)軸；長(zhǎng)方形有2對(duì)稱(chēng)軸；正方形有4對(duì)稱(chēng)軸．
故答案為：無(wú)數(shù)；1；2；4．
點(diǎn)評(píng)：此題考查了對(duì)稱(chēng)軸的定義和如何確定對(duì)稱(chēng)軸的條數(shù)．