三角形的高、中线和角平分线是三角形中的三种重要线段 ,与三角形的中线和角平分线不同的是三角形的三条高不一定都在三角形的内部 ,而同学们在实际解题中常常淡忘了这一点 ,从而造成解题的漏解错误 .下面举例说图 1明 .例 1　若等腰三角形一腰上的高与另一腰的夹角为 45° ,则 The triangle’s high, midline, and angle bisectors are the three important line segments in the triangle. Unlike the triangle’s midline and angle bisectors, the triangle’s three heights are not always within the triangle’s interior. Students often do the same in practical problems. Oblivion this point, resulting in the solution to the problem of misinterpretation errors. The following example illustrates Figure 1. Example 1. If the isosceles triangle at one waist and the other waist angle is 45 °, then