已知:如图,在
中,
于点H,D,E,F分别是
,
,
的中点.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff4744b427f036dfbc6db68c87cd5c54.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3def8acd35e11de2e1f256d51095c079.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/8293a742-e947-4274-b34b-1da321c90c4a.png?resizew=186)
21-22八年级下·全国·课后作业 查看更多[1]
(已下线)【浙教版课时练习】八年级下册第4章 目标与评定
更新时间:2022-11-28 20:49:14
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相似题推荐
解答题-证明题
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适中
(0.65)
【推荐1】在研究三角形中点或中线问题时,常采用延长中线一倍的办法,此法称为:倍长中线.
(1)【原题呈现】八年级上册课本P27:如图①,在
中,
是
边上的中线,点
在
的延长线上,且
.请证明:
.
(2)【思路探究】如图②,已知线段
.求作:
,使
边上的中线
.请完善以下作图思路,并填写相应的作图依据.
①已知共顶点两边
,要想作出
,还需要知道
或
.若知道
,则可以根据______作出符合条件的
;若知道
,则可以根据______作出符合条件的
;但目前只知道中线
,所以不能直接作出
.
②根据第(1)题,获得思路.可以作出边为
的
.此作图过程需先做出一条线段等于线段
的两倍,然后依据______作出
.
③在
上截取
得
的中点
,连接
并延长至点
,使得______,可得
.
(3)【迁移运用】请根据上述(1)(2)问的证明和思考过程,直接作出满足下列条件的三角形(
)若用其他思路,作法正确也可以.
作等腰
,满足腰
,底边
上的高
.
(1)【原题呈现】八年级上册课本P27:如图①,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2b34233772c4c26d6669499d9b1f15a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcb0803e134a985e6b444138f75968d9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/11/f9ceac8d-5418-4679-8e39-c67f4028e6fe.png?resizew=245)
(2)【思路探究】如图②,已知线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f7f443b7d4efacaaf46340a1fe65ef8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75599be9315048da76c2ccd4aa495605.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3be96420ac78c8621fcb47a45514fa8.png)
①已知共顶点两边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf9a415bdb7b4e1e35c18a9e53205392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21b28f28ced0531d1df34fcf04c6c67f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21b28f28ced0531d1df34fcf04c6c67f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
②根据第(1)题,获得思路.可以作出边为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3eee4e3576c0b13805aade8173dcbeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
③在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(3)【迁移运用】请根据上述(1)(2)问的证明和思考过程,直接作出满足下列条件的三角形(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62cf1837d2906eff2cea231333490e4d.png)
作等腰
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c716b3f1b224bd45eb797f598b895e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d29972bb7e1da354a460f22f7516805a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/11/6bf45a46-3e72-4bf0-a469-bfe10933a598.png?resizew=91)
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【推荐2】如图,已知:AB=AC,BD=CD,点P是AD延长线上的一点,且PB⊥AB,PC⊥AC.求证:PB=PC.
![](https://img.xkw.com/dksih/QBM/2019/1/1/2109234591424512/2110806076465152/STEM/8d238c2d613c482ca6988d8eeb0fb6bc.png?resizew=144)
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【推荐1】如图,△ABC中,AD是中线,AE是角平分线,CF⊥AE于F,AB=10,AC=6,求DF的长.
![](https://img.xkw.com/dksih/QBM/2019/10/9/2308093897277440/2311158495608832/STEM/7b498116-c423-475e-a1a2-03630a72978f.png?resizew=182)
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【推荐2】如图,AD∥BC,点E是AB的中点,联结DE并延长交CB的延长线于点F,点G在边BC上,且∠GDF=∠ADF.
![](https://img.xkw.com/dksih/QBM/2022/1/30/2905614341554176/2930239917776896/STEM/76997244e9b54584bafb973b4200a9f3.png?resizew=191)
(1)求证:AD=BF;
(2)当点G是FC的中点时,判断△FDC的形状.
![](https://img.xkw.com/dksih/QBM/2022/1/30/2905614341554176/2930239917776896/STEM/76997244e9b54584bafb973b4200a9f3.png?resizew=191)
(1)求证:AD=BF;
(2)当点G是FC的中点时,判断△FDC的形状.
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【推荐1】如图,在四边形
中,
,
,
.
是矩形;
(2)点E是
上一点,点
是
的中点,连接
,
,
,若
,
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d2530e7023b2345c651e8f53629ff1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
(2)点E是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0213c5787a5a6b38d11bceca5567f67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0215e13a9fb5574d5194aeb9507a98aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662a9a633cdf3c5f19105025d69fc089.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8832c5450a61500ccbf73d95e16f449.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df049f15adb6667113ceee3a6638cd0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0215e13a9fb5574d5194aeb9507a98aa.png)
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【推荐2】如图,在△ABC中,∠ABC=90°,AC的垂直平分线分别与AC,BC及AB的延长线相交于点D,E,F,点O是EF中点,连结BO井延长到G,且GO=BO,连接EG,FG
(1)试求四边形EBFG的形状,说明理由;
(2)求证:BD⊥BG
(3)当AB=BE=1时,求EF的长,
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/16/18887779-2536-4c7f-a707-22dd60396b55.png?resizew=142)
(1)试求四边形EBFG的形状,说明理由;
(2)求证:BD⊥BG
(3)当AB=BE=1时,求EF的长,
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