1 . 综合与实践:
(1)三角形中位线定理:如图①,在
中,点D,E分别是边
,
的中点.请直接写出中位线
和第三条边
的位置关系和数量关系;
【知识应用】
(2)如图②,在四边形
中,点E,F分别是边
,
的中点,若
,
,
,
,求
的度数.
(1)三角形中位线定理:如图①,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
【知识应用】
(2)如图②,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ebb33adb2310a6e03918761e68204a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de8cc58ef27567f0ab06eb1012aec330.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1496042c1d721cffd25053e997a9a97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c8d1822c76e27b3d18a9b47eaa9d734.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
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2 . 如图,
对角线
、
相交于点
,
为
中点,
,
,则
的周长为______ .
![](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/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86338536656046e93b53672ade9a78b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48813b8fc61cdb0c54fbc6a2e4bbd30b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
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3 . 如图,
中,
、
、
分别为
、
、
的中点,
为
上任一点,若
,则图中阴影部分的面积为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5138a9f70d5e8b0580e30fef6eb7baef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f61b60525064ce6947e43c39fdda6442.png)
A.![]() | B.![]() | C.![]() | D.无法确定 |
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4 . 【教材呈现】如图是华师版九年级上册数学教材第77页的部分内容.
(2)【定理应用】如图②,已知矩形
中,
,
,点P在
上从B向C移动,R、E、F分别是
的中点,则
________
猜想:如图,在![]() ![]() ![]() 根据画出的图形,可以猜想: ![]() ![]() 对此,我们可以用演绎推理给出证明. |
(2)【定理应用】如图②,已知矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/267ace52b64e1e7dfc5211e033255b7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0861e2b4eaa8ca1caf6bbde70cff4c85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a71a9d21f77e9535de152bb33f802bb.png)
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5 . 【综合与实践】
【探究】(1)小学我们就学过同底等高的两个三角形的面积相等,后来我们又学到等高的两个三角形的面积之比等于与高对应的底边长之比,如图(1),
的高
和
的高
相等,则
同样,同底的两个三角形,如果面积相等,也有类似的结论,若图形位置特殊,由此会产生一些新的结论,下面是小江同学探索的一个结论,请帮助小江完成证明.
和
的面积相等,求证:
.
证明:分别过点
、点
作
和
底边
上的高线
,
.
【应用】(2)把图(3)的四边形
改成一个以
为一边的三角形,并保持面积不变,请画出图形,并简要说明理由.
【拓展】(3)用上述探究的结论和已经证明的结论,证明三角形的中位线定理.
已知:如图(4),______.
求证:______.
证明:
【探究】(1)小学我们就学过同底等高的两个三角形的面积相等,后来我们又学到等高的两个三角形的面积之比等于与高对应的底边长之比,如图(1),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36e5e61804ce550636a0354e0a78a22d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/301941880d65680d8133f05b2785ce64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f0dadf037efedc90b39c57a6880a1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
证明:分别过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f0dadf037efedc90b39c57a6880a1a.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/d004d2d115b477ade6af7ddb93db0df8.png)
【应用】(2)把图(3)的四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
【拓展】(3)用上述探究的结论和已经证明的结论,证明三角形的中位线定理.
已知:如图(4),______.
求证:______.
证明:
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7日内更新
|
101次组卷
|
2卷引用:浙江省杭州市萧山城区8校联考2023-2024学年九年级下学期4月期中考试数学试题
6 . 如图,在
中,
,点D,E分别是直角边
的中点,则
的长为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b63785e81bc94b3c83a7e5729f924a18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa49835cb36d11ba406fa8cabbecd69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
您最近一年使用:0次
7 . 定义.对于一个四边形,我们把依次连结它的各边中点得到的新四边形叫做原四边形的“中点四边形”,如果原四边形的中点四边形是个正方形,我们把这个原四边形叫做“中方四边形”.
概念理解:下列四边形中一定是“中方四边形”的是______________
A.平行四边形 B.矩形 C.菱形; D.正方形.
性质探究:如图1,四边形
是“中方四边形”,观察图形,写出关于四边形
性质的一条结论:___________
问题解决:如图2,以锐角
的两边
为边长,分别向外侧作正方形
和正方形
,连结
.
是“中方四边形”;
拓展应用:如图3,已知四边形
是“中方四边形”,M,N分别是
的中点.
(2)若
,则
_________;
(3)若
的最小值是2,则
的长度为_________;
概念理解:下列四边形中一定是“中方四边形”的是______________
A.平行四边形 B.矩形 C.菱形; D.正方形.
性质探究:如图1,四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
问题解决:如图2,以锐角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17487118ab7a90fc8c91bf0870f3289e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3a079cfdcca9acdacecbf08f9f78cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff7a0bfc593a8a33b6cade6ba213904c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a58bcffc28a1d6bfdfd04a4abed39d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/693cd6179b2a92f03153ce12a0e86b95.png)
拓展应用:如图3,已知四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdcf86f7cf381c563ad80af86feeed83.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/056c2272e0d10d6dd9706e6324d8e62d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c978d92edf0c4c1ef8620c17df75d35e.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1aac055263010139f6eb4df68f9d619.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
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8 . 如图,菱形
的对角线
,
相交于点O,
于点E,F是
的中点,
于点G.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/6/17/c5ff4ce6-0521-4ad8-aa4f-47eafa686963.png?resizew=254)
(1)求证:四边形
是矩形;
(2)若
,
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b38f73cb3327c66fe896003b81c32486.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57e3e8c0bfb70f664bbce7affbba2862.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/6/17/c5ff4ce6-0521-4ad8-aa4f-47eafa686963.png?resizew=254)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d04bbe52e0dc7321ef0dfbe589ee52fd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e3bc4de1b5cd2a569b139d6a7a4c214.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8f954f761702d49c5c9403e1a471143.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5a278cc29e6adcb842d5ad1de09f6e6.png)
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9 . 如图,在边长为3的正方形
的外侧,作等腰三角形
.若F为
的中点,连接
并延长,与
相交于点G,则
的长为_______
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5119642a862556a4434d7248265a895.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efa9fbcfb9595e2f031aa691db4564b.png)
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10 . D、E分别是不等边三角形
(即
)的边
、
的中点.O是
所在平面上的动点,连接
、
,点G、F分别是
、
的中点,顺次连接点D、G、F、E.
的内部时,求证:四边形
是平行四边形;
(2)若四边形
是菱形,则
与
应满足怎样的数量关系?(直接写出答案,不需要说明理由.)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/787ac5e13622afab5e9f8603afe42356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14b1789f2135b9bfc56aab3f5d00ba67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d62e8aadaadebf1454fde21a390ebdea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6967ebd791092c62b4ef97924d91883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d62e8aadaadebf1454fde21a390ebdea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6967ebd791092c62b4ef97924d91883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61d1c53840b6405b2004a41272ae2700.png)
(2)若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61d1c53840b6405b2004a41272ae2700.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae7a3e520a16d4fdd73c4e6a4ce7be0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
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