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)
更新时间:2024-01-29 15:39:58
|
相似题推荐
解答题-问答题
|
较难
(0.4)
【推荐1】操作探究
(1)如图1,在平面直角坐标系中,有点
和
,利用直尺在x轴上找一点P,使点P到点A和点B的距离之和最小,标出点P的位置并简单说明作法(不用说明原理);
问题探究
(2)如图2,在
中,
,D、E、F分别在
上,
,若
,求
;(用含
的式子表示)
问题解决
(3)如图3,有一片形状为菱形
的湿地,
,点A、C之间的距离为
,计划在湿地内圈出一个动物保护区(即
区域),点E、F分别在线段
上,
,点A和点O是巡视员休息站,点O是菱形
的对称中心.为方便定时检查动物保护区,现要沿
开辟两条笔直的小道,根据要求小道
和
的总长要尽可能的小.问
的长度存在最小值吗?若存在,请求出
的最小值:若不存在,说明理由.
(1)如图1,在平面直角坐标系中,有点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fbae88c482ffc9f523e70d5a405bffb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ad80544a83929c7162e3e9fe5bb250.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/8/d9ef1675-ed53-4a14-b6de-db699a7d66a7.png?resizew=193)
问题探究
(2)如图2,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/a8b2a11d2790d89247e2606fb0b233f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b672a8448993657823fe9c9e128e6c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fd465973943bcd766b5275ee204bbf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c962fe4f47732b8e6e83d17ff2b9af13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/8/9b03312f-3330-421f-ae99-026f1b377314.png?resizew=138)
问题解决
(3)如图3,有一片形状为菱形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/695525d00319665b1ad0d01717979523.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2bd4f1b3a3f3e534c5c3b39266f1ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36e5e61804ce550636a0354e0a78a22d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a35bbf1c5259939f288cb0bc65e6ceb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/789c917f257d0b1440b5bb02227d3ce4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39e2709897c04475e8041ac4947fb8f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307bd991211ec79b47a4be52933bb8e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afa7d288a5c3830419fd71b8d4fd22c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afa7d288a5c3830419fd71b8d4fd22c8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/8/54215e01-4961-4a24-9893-617254553ffb.png?resizew=174)
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解答题-证明题
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【推荐2】问题:在△ABC中,AB=6,AC=4,AD是△ABC的中线,求线段AD长度的取值范围.
![](https://img.xkw.com/dksih/QBM/2022/3/7/2931333025300480/2938949394636800/STEM/f241e7ee22aa49c0894495d5ff750c1b.png?resizew=414)
(1)探究:如图1,我们可以延长AD到E,使DE=AD,连接BE,求证:△BED≌△CAD;
(2)解决问题:求线段AD长度的取值范围;
(3)方法运用:
如图2,在矩形ABCD中,
,在对角线BD上取一点F,以BF为斜边在左上方作Rt△BEF,且
,点G是DF的中点,连接EG,CG,求证:EG=CG.
![](https://img.xkw.com/dksih/QBM/2022/3/7/2931333025300480/2938949394636800/STEM/f241e7ee22aa49c0894495d5ff750c1b.png?resizew=414)
(1)探究:如图1,我们可以延长AD到E,使DE=AD,连接BE,求证:△BED≌△CAD;
(2)解决问题:求线段AD长度的取值范围;
(3)方法运用:
如图2,在矩形ABCD中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a54049b5c43495c4f00f7a364cc5b8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72b9bf93660eb49c1b049595f5f7700d.png)
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【推荐1】已知等腰Rt△ABC,∠BAC=90°,AB=AC,点D为△ABC内部一点,连接AD、BD、CD,点H为BD中点,连接AH,且∠BAH=∠ACD.
(1)如图1,若∠ADB=90°,求证:∠DAH=45°;
(2)如图2,若∠ADB<90°,(1)问中的结论是否成立,若成立,请证明;若不成立,请说明理由.
(1)如图1,若∠ADB=90°,求证:∠DAH=45°;
(2)如图2,若∠ADB<90°,(1)问中的结论是否成立,若成立,请证明;若不成立,请说明理由.
![](https://img.xkw.com/dksih/QBM/2019/1/10/2115884278816768/2160300956442624/STEM/0d3caf3d6dbb4269b49c0f1663f0550e.png?resizew=234)
![](https://img.xkw.com/dksih/QBM/2019/1/10/2115884278816768/2160300956442624/STEM/364cdc52b831421cb3837c94ad6a3da9.png?resizew=253)
您最近一年使用:0次
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较难
(0.4)
【推荐2】如图1,
和
都是等腰直角三角形,
,将△BDE绕点B逆时针旋转
(
),连接
,取
中点F,连接
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/17/d243abc6-162d-4387-a2de-5b23b552b327.png?resizew=568)
(1)如图1,当点D落在
边上,点E落在
边上时,线段
和线段
的位置关系是_____,数量关系是______;
(2)如图2,当点D落在
内部时,(1)的结论是否仍然成立?如果成立,请写出证明过程;如果不成立,请说明理由.
九年级一班数学兴趣小组的同学提出了三种思路:
小聪:过点D作
交线段
于点M,过点A作
交线段
于点N……
小明:延长
至点G,使
,延长
至点H使
,连接
、
……
小智:延长
至点P,使
,连接
,
,
……
请你选择一种思路,完善证明过程;
(3)若
,
,在
旋转的过程中,当点E,D,F三点共线时,连接
,请直接写出
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/321370fe42bc1216902ea19fbd2a5979.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ac9b2894db7b1577f94596a52a86a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2adc42e4d1370a6ad18ca847d93bfc22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/17/d243abc6-162d-4387-a2de-5b23b552b327.png?resizew=568)
(1)如图1,当点D落在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(2)如图2,当点D落在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
九年级一班数学兴趣小组的同学提出了三种思路:
小聪:过点D作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4ed289f51942bd8626ce727b43be1d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ab7c7e6678695363cb5f4319e68bc52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
小明:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f46d93b877d359a4218e156b46d5aa3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/350b9e6ed43616c5b34aae8fb5821b26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4083c581c6027c4b2ae7e3b3749f485.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
小智:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7291981bcee8ab913100b606ba49fa4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
请你选择一种思路,完善证明过程;
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714cc3707bba3bfdb56e251999be8592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15514bc735fe4b744672edefe00009c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
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解答题-问答题
|
较难
(0.4)
名校
【推荐1】综合与实践:某数学活动小组在探究三角形时,提出了如下数学问题:
![](https://img.xkw.com/dksih/QBM/2022/6/30/3012573817536512/3040304443154432/STEM/af6c0f6b3b2442b78b55541bec31272a.png?resizew=507)
问题提出:
(1)已知:如图1所示,平面内三个点A,B,C,
,
.如图1,BC的长度的最小值为________.
问题解决:
(2)已知:如图2所示,在
中,
,
,以BC为底边向上构造等腰
,
,连接AD,以AD为腰向外构造等腰
,使
,且
,线段DE的长度是否存在最小值?若存在,请求出最小值:若不存在,请说明理由.
问题应用:
(3)如图3所示,在
中,
,
,
,以AC为边向外作等边
,连接BD.求BD的长度.
![](https://img.xkw.com/dksih/QBM/2022/6/30/3012573817536512/3040304443154432/STEM/af6c0f6b3b2442b78b55541bec31272a.png?resizew=507)
问题提出:
(1)已知:如图1所示,平面内三个点A,B,C,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
问题解决:
(2)已知:如图2所示,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e3a9ec45721f7b4d1c99917ac0d970f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eb3d1070981fed5ca65a34bb2282e6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](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/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8abfdaab699cfe51bb9678110ad6aee.png)
问题应用:
(3)如图3所示,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fb01d2b57580731c8b807ac8cffc8ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78b65065ec3a0cb4b050989165c003d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65fc998d33cdf37c272f79cfd64b7b99.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
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(0.4)
名校
【推荐2】如图,
是圆
的直径,弦
于点
,
是
上一点,
,
的延长线交于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/18/7d16aa75-972d-4cac-98d0-c32c9d98c9ae.png?resizew=148)
(1)求证:
.
(2)若
平分
,
,
,求
的长.
(3)若
,
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/667349d99185bb045030b733352ff7fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/18/7d16aa75-972d-4cac-98d0-c32c9d98c9ae.png?resizew=148)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a0ddf9abe631261a5049500c0090927.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96dbf32210f81599fa2a02983ac84cac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41677cc3390e002d9459f0bb89c7e605.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27d3ab0b6248171640cc638504dd0ef5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ead1eda1ca5b67586379a09a4c3540b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】如图,
为
的直径,弦
于点E,点F在
上,连结
并延长交
与点G,连结
,
.
;
(2)如图2,
与
交于点N,过点F作
的平行线交
于点M,若
,求
.(用含a的代数式表示)
(3)如图3,在(2)的条件下,连结
,若
与
的面积相等,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe14ba8d6549cee1751bb4fc1e32651.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8fb80f198f13fa35b1a2e518f9be444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d65a5303d503df1ec010187e70d64d18.png)
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1a1536c6b2e820359c6d917b71a81f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
(3)如图3,在(2)的条件下,连结
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91f3956f008cc29ca4bae44a087d5427.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36e5e61804ce550636a0354e0a78a22d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2495b77f64c4106112eb1709f99f43cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d54d09ef825305de83671448a3dea21.png)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐2】如图,已知点O为△ABC的内心,连AO、BO、CO,过点O的直线分别交边AB、AC于点M、N,
![](https://img.xkw.com/dksih/QBM/2014/12/29/1573779137445888/1573779143172096/STEM/1c860be4266c468e8097b35ebce80136.png)
图一 图二
(1)若∠BAC=70°,那么∠BOC= °;
(2)如图1,若MN∥BC,BM=2,CN=3,求线段MN的长;
(3)如图2,若MN⊥AO,BM=2,CN=3,求线段MN的长.
![](https://img.xkw.com/dksih/QBM/2014/12/29/1573779137445888/1573779143172096/STEM/1c860be4266c468e8097b35ebce80136.png)
图一 图二
(1)若∠BAC=70°,那么∠BOC= °;
(2)如图1,若MN∥BC,BM=2,CN=3,求线段MN的长;
(3)如图2,若MN⊥AO,BM=2,CN=3,求线段MN的长.
您最近一年使用:0次