题干

如图,CD,EF表示高度不同的两座建筑物,已知CD高15米,小明站在A处,视线越过CD,能看到它后面的建筑物的顶端E,此时小明的视角∠FAE=45°,为了能看到建筑物EF上点M的位置,小明延直线FA由点A移动到点N的位置,此时小明的视角∠FNM=30°,求AN之间的距离.

上一题 下一题 0.0难度 选择题 更新时间:2018-10-11 11:23:29

答案(点此获取答案解析)

由题意可知:∠CDA=90°;
在Rt△CAD中,∠CDA=90°,∠CAD=45°,CD=15,

在Rt△CDN中,∠CDN=90°,∠CND=30°,

同类题2

通读全文, 根据短文内容的理解, 选择最佳答案填空。

Unchangeable Love

    One day I visited an art museum while waiting for my husband to finish a business meeting. I was expecting a quiet 1 of the splendid artwork.

    A young 2 viewing the paintings ahead of me 3 nonstop between themselves. I watched them a moment and decided the lady was doing all the talking. I admired the man's 4 for putting up with her 5 stream of words. 6 by their noise, I moved on.

    I met them several times as I moved 7 the various rooms of art. Each time I heard her continuous flow of words, I moved away 8.

    I was standing at the counter of the museum gift shop making a 9 when the couple approached the 10. Before they left, the man 11 into his pocket and pulled out a white object. He 12 it into a long stick and then tapped his way into the 13 to get his wife's jacket.

     "He's a 14 man." the clerk at the counter said. "Most of us would give up if we were blinded at such a young age. During his recovery, he made a promise his life wouldn't change. So, as before, he and his wife come in 15 there is a new art show."

     "But what does he get out of the art?" I asked. "He can't see."

     "Can't see! You're 16. He sees a lot. More than you and I do," the clerk said. "His wife 17 each painting so he can see it in his head."

    I learned something about patience, 18 and love that day. I saw the patience of a young wife describing paintings to a person without 19 and the courage of a husband who would not 20 blindness to change his life. And I saw the love shared by two people as I watched this couple walk away, hand in hand.