亚洲男人天堂av,国产一区二区久久精品,国产精品一区二区久久精品,国产精品久久久久久一区二区三区,五月婷婷在线观看视频,亚洲狠狠色丁香婷婷综合

歡迎您訪問數學考題練習:如圖,邊長為的正方形ABCD繞點A逆時針旋轉3!

數學考題練習:如圖,邊長為的正方形ABCD繞點A逆時針旋轉3

更新時間:2024-01-12 16:29:30作者:貝語網校

如圖,邊長為的正方形ABCD繞點A逆時針旋轉30°到正方形AB′C′D′,圖中陰影部分的面積為

A.

B.3-

C.

D.3-

試題答案

B

試題解析

連接AE,根據∠BAB′=30°可知∠DAB′=60°,由正方形的性質可知,AB=AD,由圖形旋轉的性質可知AD=AB′,故可得出Rt△ADE≌Rt△AB′E,由直角三角形的性質可得出DE的長,再由S陰影=S正方形ABCD-S四邊形ADEB′即可得出結論.

解答:解:連接AE,

∵∠BAB′=30°,

∴∠DAB′=60°,

∵四邊形ABCD是正方形,

∴AB=AD,∠D=∠B=90°,

∵正方形AB′C′D′是正方形ABCD旋轉而成,

∴AD=AB′,∠B′=90°,

在Rt△ADE與Rt△AB′E中,AD=AB′,AE=AE,

∴Rt△ADE≌Rt△AB′E,

∴∠DAE==30°,

∴DE=AD•tan∠DAE=×=1,

∴S四邊形ADEB′=2S△ADE=2××AD×DE=,

∴S陰影=S正方形ABCD-S四邊形ADEB=3-.

故選B.

點評:本題考查的是圖形旋轉的性質,涉及到正方形的性質、銳角三角函數的定義及特殊角的三角函數值,涉及面較廣,難度適中.

主站蜘蛛池模板: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |