也是軸對(duì)稱圖形;兩組對(duì)邊分別平行且相等;有2條對(duì)稱軸;長(zhǎng)方形的周長(zhǎng)單位是什么,如:千米、米、厘米、分米、毫米等,正方形是特殊的長(zhǎng)方形,兩條對(duì)角線相等,再乘以2,