Question

圓有

無(wú)數(shù)

條對(duì)稱軸，長(zhǎng)方形

2

條對(duì)稱軸，正方形有

4

條對(duì)稱軸，平行四邊形

0

條對(duì)稱軸．

Answer 1

分析：根據(jù)軸對(duì)稱圖形的概念求解．如果一個(gè)圖形沿著一條直線對(duì)折后兩部分完全重合，這樣的圖形叫做軸對(duì)稱圖形，這條直線叫做對(duì)稱軸．

解答：解：根據(jù)軸對(duì)稱圖形的定義可知：圓有無(wú)數(shù)條對(duì)稱軸，長(zhǎng)方形有2條對(duì)稱軸，正方形有4條對(duì)稱軸，平行四邊形有0條對(duì)稱軸．
故答案為：無(wú)數(shù)；2；4；0．

點(diǎn)評(píng)：本題考查軸對(duì)稱圖形的知識(shí)，要求掌握軸對(duì)稱圖形的概念．軸對(duì)稱圖形的關(guān)鍵是尋找對(duì)稱軸，圖形兩部分折疊后可重合．