三角形中(内、外)角平分线的交角计算,因其过程中涉及的知识较多,综合性较强,从而成为几何问题中的一个重点和难点.现就最基本的三角形中,交角的计算公式加以归纳、推导,供大家参考.一、两内角平分线交角例1如图1,ABC中,∠ABC、∠ACB的平分线交于点D,试用∠A表示∠BDC的度数.分 The calculation of the angle of intersection of the bisector (inside and outside) bisectors in the triangle is a key and difficult issue in the geometry because of the more knowledge involved in the process and the more comprehensive nature. The calculation formula is summarized and deduced for your reference. First, the angle between the two internal angle bisectors is shown in Figure 1. In ABC, the bisectors of ∠ABC and ∠ACB are intersected at point D. The trial ∠A indicates the degree of ∠BDC.