我们经常遇到需要分类的问题,画“树形图”可以帮我们不重复、不遗漏地分类.
【问题提出】
(1)在等腰三角形ABC中,若∠A=80°,根据下面分析、直接写出∠B的度数___________.
分析:∠A、∠B都可能是顶角或底角,因此需要分成如图所示的3类,这样的图就是树形图.请根据此分析、求出∠B的度数.
【问题解决】
(2)已知等腰三角形ABC周长为19,AB=7,仿照例题画出树形图,并求出BC的长度.
【问题提出】
(1)在等腰三角形ABC中,若∠A=80°,根据下面分析、直接写出∠B的度数___________.
分析:∠A、∠B都可能是顶角或底角,因此需要分成如图所示的3类,这样的图就是树形图.请根据此分析、求出∠B的度数.
【问题解决】
(2)已知等腰三角形ABC周长为19,AB=7,仿照例题画出树形图,并求出BC的长度.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/12/eb3050dd-391b-4aa3-b2ea-21167d7a6b71.png?resizew=304)
更新时间:2021-11-26 09:25:29
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