题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040757-63266.jpg)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040758-55394.png)
解析
试题分析:如图,依题意有,AC=15×4=60,∠CAB=30°,∠ABC=45°,
在△ABC中,由正弦定理得
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040758-14074.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040758-27737.png)
故答案为30
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040758-27737.png)
点评:简单题,处理这类问题,要弄清实际问题中确定的三角形的边角,以正确地选用正弦定理或余弦定理。
核心考点
试题【一船以每小时15 km的速度向东航行,船在A处看到一个灯塔B在北偏东60°,行驶4 h后,船到达C处,看到这个灯塔在北偏东15°,这时船与灯塔的距离为_____】;主要考察你对解三角形应用等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040751-49374.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040751-41441.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040751-14727.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040751-27170.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040752-74273.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040752-34191.png)
(1)角
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040752-12384.png)
(2)边
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040752-20544.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040745-53299.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040746-30923.png)
(1)求角
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040746-32999.png)
(2)如果
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040746-73468.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040746-24073.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040746-59737.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040747-29031.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040739-57095.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040739-79817.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040740-24758.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040740-36986.png)
(1)若
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040740-24801.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040740-95302.png)
(2)若
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040741-36137.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040741-73891.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040732-40069.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040733-64704.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040733-84434.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040733-64277.png)
(Ⅰ)求角
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040733-39475.png)
(Ⅱ)若
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040734-16069.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040734-73070.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040734-26297.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040729-30823.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040729-77589.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020040729-66301.png)
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