1 . 综合与实践
问题情境
在
中,
,点O是
的中点,D为
内一点,连接
,将线段
绕着点O旋转
得到
,连接
.
探究证明
(1)如图1,延长
交
于点E,若
.求证:
;
(2)如图2,连接
,交
的延长线于点G,连接
,若
,用等式表示线段
之间的数量关系,并证明;
拓展提升
(3)如图3,在(2)的条件下,
与
交于点H,若
,
,
,请求出
的长度(直接写出答案).
问题情境
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.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/47d6e9a08075156a32fbf5571f94e50c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71b63d2504bd3ecce8c10560b142356f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfe639eab78eafd2d40ea70aa5d3f21d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecff6005f926665a926c07ad62e0f032.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
探究证明
(1)如图1,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d320f180419175d75eebc618cc458b39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2d1e129bc533d229524e985ad9a1f41.png)
(2)如图2,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307bd991211ec79b47a4be52933bb8e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebba1f34ceeeda357c6796d4dfc4a19c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/deac72df325262c458af3adca9d08542.png)
拓展提升
(3)如图3,在(2)的条件下,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f25936291abb6432ed5a710ebf0ea195.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7976a5206126665cc0d66deae52b3b1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/29/048cf7b6-94e2-4f0e-b4fd-47d472b51c1a.png?resizew=406)
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2 . 如图,
,
,
相交于点O,若
,则
的长为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/29/ba234bac-edc1-4091-8f14-b93c38660cf9.png?resizew=211)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.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/99c46ea0b74ada639c7812afb8687248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/29/ba234bac-edc1-4091-8f14-b93c38660cf9.png?resizew=211)
A.![]() | B.4 | C.![]() | D.5 |
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3 . 如图,在
中,点D、E分别是边
上的点,且
,
相交于点
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da2dc77bd22f1dd68aeaa7d86e0dfed.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0d54431bbb28ebd98db5c1dc6083a75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d021981c03e75b1a246d899dcc64656.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b75e2eaf6394f3b07703e4176541b7f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d352727e76ed3024bb342fb8a6d00177.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da2dc77bd22f1dd68aeaa7d86e0dfed.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/8a5dd234-a729-4851-8fc0-087f4a7ebbdf.png?resizew=229)
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4 . 如图,
为
的边
延长线上一点,连结
交
于点
,交
于点F,则下列式子一定正确的是:( )
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/05d57280-b85a-4f11-b7f7-5b2f3988815d.jpg?resizew=172)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc840e197de2dabff676ee1b8968fada.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/05d57280-b85a-4f11-b7f7-5b2f3988815d.jpg?resizew=172)
A.![]() | B.![]() | C.![]() | D.![]() |
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5 . 阅读以下材料,并按要求完成相应的任务.
任务:
(1)小明的证明过程中的“依据”指的是______;
(2)小亮的证明过程不完善,请你帮助小亮完成证明;
(3)如图4,在
中,
,
,
.若
的平分线
交
于点D,则
的值为______.
角平分线分线段成比例 我们知道,在数学中经过证明的真命题称为定理.下面是人们在解决数学问题时发现的一个定理,我们暂且称它为角平分线分线段成比例定理.其内容如下:如图1,在 ![]() ![]() ![]() ![]() ![]() 小明:如图2,过点A作 ![]() ![]() ![]() ∵AD是 ![]() ∵ ![]() ∵ ![]() ![]() ∴ ![]() ∵ ![]() ![]() ∴ ![]() ∴ ![]() ![]() 小亮:如图3,过点B作 ![]() ![]() ∵ ![]() ![]() ∴ ![]() ∵ ![]() ∴ ![]() …… ![]() |
(1)小明的证明过程中的“依据”指的是______;
(2)小亮的证明过程不完善,请你帮助小亮完成证明;
(3)如图4,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07160f14b3b453bebb64cb2bf96dc85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c96d049465a04bb9d09f97c0d33f7f1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/fab0c412-9924-4959-a246-771d30b631a3.png?resizew=125)
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6 . 阅读与思考
下面是小宇同学的数学论文,请仔细阅读并完成相应的任务.
任务:
(1)请把小宇证明
的过程补充完整;
(2)请求出图1中
的长度;
(3)在以上解答的启发下,请你作出图2中线段
的三等分点.
下面是小宇同学的数学论文,请仔细阅读并完成相应的任务.
利用网格构造数学图形 我们知道,由许多边长为1的正方形组成如图1所示的图形叫做网格,每一个小正方形的顶点叫做格点.利用这样的网格不仅可以构造具有位置关系的图形,还可以构造某种数量关系的图形. 在图1的网格中,连接格点 ![]() ![]() ![]() 根据网格的特征可知: ![]() ![]() ∵ ![]() ![]() ∴…… ![]() |
(1)请把小宇证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
(2)请求出图1中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
(3)在以上解答的启发下,请你作出图2中线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/32d8b09d-15f8-4088-b3f4-391f7ae1a227.png?resizew=138)
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7 . 如图,在
中,∠
,点D是
边上一动点,过点D作
于点E,
于点F,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/2f054cc0-97b7-43b1-a3ee-2aa318286931.png?resizew=164)
(1)设
,
,请确定
与
的关系式(用
表示
),并直接写出四边形DECF的面积;
(2)当
时,求
的长度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98aa2d95ef06695d19891a4b198e6233.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bffd657e48b15b9b54a55817e2c26b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/761a77e11e1e45c2a8b2d34d22cf8e04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f414cce1427646590a7f7144efe2e26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71aa812f83d86aaf308244a9afc09322.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/2f054cc0-97b7-43b1-a3ee-2aa318286931.png?resizew=164)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c421ab2dc57f44899efb36549781347.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e39f428621c72cd807963ffaae5c6d97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5490dba7da9a3f60c2f9440b2ddd0162.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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8 . 如图,在
中,
,F为
的中点,
交
于点G,且
,则下列结论错误的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c0aa4c793921fdaa5d430cb90d78ca6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a7160186d29ac0cd8da70ea8c084285.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/27/1983df1b-a8ae-4c78-8b0c-2ece9a98879b.png?resizew=149)
A.![]() | B.![]() | C.![]() | D.![]() |
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9 . 如图,正方形
的边长为4,点
是对角线
上的一点,且
,点
是边
上的一个动点,连接
,过点
作
交
于点
,当
时,线段
的长为_____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/468e20ce00520413fa22fc017f53cb46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce6c0e9de83f2e64ae33609fc08459d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30d53f8ab957921eb06016ea930bfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2765917637583d22a579ff075f9baa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/4a9dc7a0-6fda-472b-b32b-557d7727ac9c.jpg?resizew=114)
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10 . 小明下学途中遇到一棵大树,于是他想利用现有的长度为
的小尺测量这棵树的高度.如图,小明笔直站立,把手臂水平向前伸直,将小尺竖直举起,瞄准小尺的两端
,
,然后不断调整站立的位置,在点
处时恰好能看到该大树的顶端
和底部
.(图中所有点均在同一平面,点
,
,
在同一条直线上.)经测量,小明的手臂长
,点
到树底端的距离
,求大树
的高度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc31bf4b6ed8cf336432a5a2791e67e3.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0eab4eade3f344bb074a3d53e307ccf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ce8c74020fcd09bc8d83b8b92963e18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/28/62b84fc0-0ab8-4f22-ba4c-2f21d3042775.png?resizew=183)
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