【问题原型】如图,在
中,对角线
的垂直平分线
交
于点F,交
于点E,交
于点O,连接
,
.求证:四边形
是菱形.
【甲同学的证法】证明:
垂直平分![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
,(第一步)
(第二步)
四边形
是平行四边形(第三步)
又
(第四步)
∴四边形
是菱形(第五步)
【老师评析】甲同学想先利用对角线互相平分证明四边形
是平行四边形,再利用对角线互相垂直证明它是菱形,可惜有一步错了.
【挑错改错】
(1)甲同学的证明过程在第______步出现了错误;
(2)请你根据甲同学的证明思路写出此题正确的证明过程;
(3)直接写出当
中的
______时,四边形
是正方形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
【甲同学的证法】证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/173f7d26d069c0f16a0f6fcb517aa28c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb7475a34bbc1cd1e1b468056d087828.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed9e9efc81c91390a1c25647f5bf8750.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bdbad69a82cc225f143e384c0f25de5.png)
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
【老师评析】甲同学想先利用对角线互相平分证明四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
【挑错改错】
(1)甲同学的证明过程在第______步出现了错误;
(2)请你根据甲同学的证明思路写出此题正确的证明过程;
(3)直接写出当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41db498f025052df2dbb1e50ab672675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910936ec9fb419d51ce2f5ea817f8401.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/15/1db47677-5ba6-4400-b7ed-12a6c3d6a79f.jpg?resizew=168)
更新时间:2023-07-09 06:53:09
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【推荐2】如图,E为
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