1 . 已知四边形
为正方形,点E在
边上,连接
.
于点H,交
于点F(保留作图痕迹,不写作法,不下结论);
(2)求证:
.(请补全下面的证明过程)
证明:∵正方形![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
,
① ![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0c06422e1d55db3077257af113df4bb.png)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4500c083ce75a99fd640c3067e600d9.png)
∵![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb91cb9a5a14169845d700fbd95890ac.png)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17d2242e660785814aa933b93ea28a0e.png)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdf65f2f3f02118a8956c76ba9f55fae.png)
∴ ②
在
与
中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0bf7dac56228861cfa32b49e3b0029f.png)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7524efde0a1e83b66363b141d64ca98.png)
∴
④ .
通过上面的操作,进一步探究得到这样的结论:两端点在正方形的一组对边上且 ⑤ 的线段长相等.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb91cb9a5a14169845d700fbd95890ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04f8eebda19eded2b059774a8c2666c3.png)
证明:∵正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3570a95f68349fcd9417fcda62e78e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ba465710fe3b2f262c9660d25016ffa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0c06422e1d55db3077257af113df4bb.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4500c083ce75a99fd640c3067e600d9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb91cb9a5a14169845d700fbd95890ac.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17d2242e660785814aa933b93ea28a0e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdf65f2f3f02118a8956c76ba9f55fae.png)
∴ ②
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6830ebecddbd9759be626289c408e4f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0bf7dac56228861cfa32b49e3b0029f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7524efde0a1e83b66363b141d64ca98.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32217457c4e96e2ef155cf15c1b65d97.png)
通过上面的操作,进一步探究得到这样的结论:两端点在正方形的一组对边上且 ⑤ 的线段长相等.
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2024-01-29更新
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4卷引用:重庆市潼南区2023-2024学年九年级下学期月考数学试题