角平分线是初中几何学习中的一个重点,与之相关的考题在各种考试中经常出现.解答它们的方法因题而异,现举例如下:一、利用角平分线定义角平分线定义是,从一个角的顶点出发,把这个角分成两个相等角的射线.例1如图1,在△ABC中,AD平分∠BAC且与BC相交于点D,∠B=40°, The angle bisector is a key point in junior high school geometry learning, and the related test questions often appear in various examinations. The way to answer them varies with different topics. The examples are as follows: First, use the angle bisector to define the angle bisector. , Starting from the vertex of one corner, the corner is divided into two equal-angle rays Example 1 As shown in Figure 1, in Δ ABC, AD bisects ∠BAC and intersects BC at point D, ∠B = 40 °,