角平分线与等腰三角形有着紧密的联系.比如,在许多几何问题中,遇到等腰三角形就会想到顶角的平分线,遇到角平分线又会想到构造等腰三角形.下面,分类举例说明..一角平分线+平行线→等腰三角形当一个三角形中出现角平分线和平行线时,我们就可以找到等腰三角形.比如图1中,若AD平分∠BAC,AD//EC,则△ACE是等腰三角形;图2 Angle bisector and isosceles triangle are closely linked.For example, in many geometric problems, encounter the isosceles triangle will think of the bisector of the vertex, meet the angle bisector and then think of the construction of isosceles triangle.Next, the classification For example .. a corner bisector + parallel line → isosceles triangle When a triangle appears bisecting and parallel lines, we can find the isosceles triangle .As shown in Figure 1, if AD bisects ∠BAC, AD / / EC , Then △ ACE is an isosceles triangle; Figure 2