构造直角三角形的方法很多,在解答有关实际问题时,若根据需要构造直角三角形,运用勾股定理或三角函数等知识进行解答能使问题变得相对简单。现举几例进行说明,供同学们参考。1.根据测量信息构造直角三角形。例1如图1所示,BD表示一小河,河对岸有一铁塔AB,在C处测得塔顶A的仰角为30°,向铁塔方向前进16米到达D处,在D处测得A的 There are many ways to construct right-angled triangles. When answering practical questions, if you construct right-angled triangles as needed, solving them using the Pythagorean theorem or trigonometric functions makes the problem relatively straightforward. Give a few examples to illustrate for the students to reference. 1. Constructs a right-angled triangle based on the measurement information. Example 1 As shown in Fig. 1, BD represents a small river with an iron tower AB across the river. The elevation of tower A measured at C is 30 °, and the tower is advanced 16 meters to reach D at D, where A