如图,菱形
中,
,点E在边
上,点F在边
上.若E是
的中点,连接
、
、
,
,求证:F是
的中点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a39f5cd9be866438ecc64ad21a0747f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9f79d7939c88e9702962e5917cad290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff575e55857af133edb24c8e61504f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0215e13a9fb5574d5194aeb9507a98aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac0c64a010b8a7f3de794162decf23b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
更新时间:2023-11-04 10:49:48
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,在
中,
,
,点
是
上的一点,且
,
,垂足分别为点
、
,求证:
垂直平分
.
![](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/8b5f215a42c4b7078d8d65923eb9980e.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/04fb30a9d07e410ac92c34b8ad0133db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ca0940f5c21431c089d4f7a221df43c.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/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/23/8245d155-cb50-4877-8e8f-c090226e5473.png?resizew=162)
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|
适中
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【推荐2】【问题再现】如图(
),正方形
的对角线相交于点
,正方形
与正方形
的边长相等.在正方形
绕点
旋转的过程中,两个正方形重叠部分的面积(即四边形
的面积)始终等于正方形
面积的
.
【初步探究】小明在证明上述问题时,发现题目中正方形
这一条件主要用到的信息是
,图中一些线段之间也有特殊的关系.深入思考后他为大家编了如下题目:如图(
),
中,
,
,
是边
的中点.以
为顶点作
,
交线段
于点
,
交线段
于点
.请完成以下问题:
问题(1):四边形
的面积是
面积的________.
问题(2):猜想线段
之间的等量关系,并说明理由.
【延伸探究】爱动脑的小军在小明问题的基础上进行了延伸,让
绕点
旋转,
交直线
于点E,
交直线
于点
,连接
.若
,
,请直接写出
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c29feba6e7ec88196414dcd7d9ba68e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c29feba6e7ec88196414dcd7d9ba68e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0463da43878c8c9848d921ecf77f1ca5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d266a04f3dc7483eddbc26c5e487db.png)
【初步探究】小明在证明上述问题时,发现题目中正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c29feba6e7ec88196414dcd7d9ba68e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a3ade4bbef1cea80d78c5bdca7e19a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b6e4a2df58a236c20df5df0d29a466c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.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/3a3ade4bbef1cea80d78c5bdca7e19a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48fce10478485ef01d2318fc3465bb4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1586d3ecae6747312b7892bac03cf8bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
问题(1):四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0463da43878c8c9848d921ecf77f1ca5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
问题(2):猜想线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95383ef9f071c41a47ef76c176dfd1c0.png)
【延伸探究】爱动脑的小军在小明问题的基础上进行了延伸,让
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba123b68d5eacc7e0f9188df08d7ae0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48fce10478485ef01d2318fc3465bb4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1586d3ecae6747312b7892bac03cf8bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adc90c2d45477e166b02359525f40aa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcc869125145c0139d92490a41bd3918.png)
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解答题-证明题
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适中
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【推荐1】如图1,在
中,
,
,点
在
边上,
于点
,过点
作
交
的延长线于点
.
(1)求证:
;
(2)如图2,过点
作
交
于点
,连接
交
于点
. 判断
的形状,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ab41054fa9ce51b68e78d9c0cf398d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4300aefd67369742e2b1ddcdc02dd495.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b909eb10b4718872a3c638bf6cfe33c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe9f641563e8533a5bb39188aa7cc182.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9f79d7939c88e9702962e5917cad290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/6/b5e8fce8-4639-461a-96a6-eeb67d43ea40.png?resizew=416)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b64c40828ef81e27c1ae55b8036d74c8.png)
(2)如图2,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47e87ae414e4d2915a15efb6275c177f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb11667abcb2759f301391b9850352be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff575e55857af133edb24c8e61504f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c12406b6f06e7f8d54d398a8f69498f0.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在
中,
是斜边
上的高线,
是
的平分线.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/11/346a5afc-c65b-4dd0-98a0-14e4e9455d62.png?resizew=210)
(1)若
,求
的度数;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/897d207d191634403e46cd39cb82592d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/11/346a5afc-c65b-4dd0-98a0-14e4e9455d62.png?resizew=210)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f0ff311a5afd6b983f03efb1a9b6af3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6282292819434a8905a212427613fd85.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d96a5d40d0aea9f4398ca4d0fe9b0dd.png)
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解答题-问答题
|
适中
(0.65)
【推荐1】如图,
为圆
的直径,取
的中点
,过点
作
交圆
于点
,
在
的上方,连接
,
,点
在线段
的延长线上,且
.
(1)求
的度数;
(2)求直线
与圆
的公共点个数.
![](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/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54f882a0e522622d35a235b7bb62d1b5.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/246a86f34603eaf2e6a948681b831b0d.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/2021/9/29/2818468245561344/2822317396492288/STEM/4d4f15c6-9233-431e-961f-fa4a3dd4dd03.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】【问题背景】
如图,在
中,
,
.
是边
上一点(不与点
重合且
),连接
,将线段
绕点
逆时针旋转
得到线段
,连接
,
.
的度数;
【拓展延伸】(2)如图2,
是
的中点,连接
并延长,交
的延长线于点
,过点
作
交
于点
,交
于点
.若
,用等式表示线段
,
,
之间的数量关系,并证明.
如图,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f76899b3a0bfbbdae7cb1148ad4bf018.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b57fdd2a3642716fcf5100011eb3ec88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ba4d62bf7a65f23b5f72d22c25996bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35803969509655f72b4118503ae1c966.png)
【拓展延伸】(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.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/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e23a577ff4bb12584e3edffb1cb6ca66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/838cd42674440f824b00c6fe88e310f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
【推荐3】阅读理解学习:
在学习《解直角三角形》这一章时,小迪同学勤学好问,在课外学习活动中,探究发现,三角形的面积、边、角之间存在一定的数量关系,下面是她的学习笔记.请仔细阅读下列材料并完成相应的任务.
【阅读材料】:在
中,
的对边分别记为
的面积记为
,过点
作
,垂足为
,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0e5738c6e0568f3678be0753a6d20d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d100b261160fa545b9429333a8d1c0.png)
同理可得:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07127e5cbeab586bd7ab9172b4946200.png)
即:
……①
由以上推理得结论①:三角形的面积等于两边及其夹角正弦积的一半.
又
,将等式
两边同除以
得
…………②
由以上推理得结论②:在一个三角形中,各边和它所对角的正弦的比值相等.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/facfe8a8-3cb2-4797-bef6-d74c03b53a13.png?resizew=144)
【理解应用】请你学习上述阅读材料解答以下问题:
如图,甲船以
海里/时的速度向正北方向航行,当甲船位于
处时,乙船位于甲船的南偏西
方向的
处,且乙船从
处沿北偏东
方向匀速直线航行,当甲船航行20分钟到达
处时,乙船航行到甲船的南偏西
方向的
处,此时两船相距
海里.
(1)求
的面积;
(2)求乙船航行的路程是多少海里(结果保留根号).
在学习《解直角三角形》这一章时,小迪同学勤学好问,在课外学习活动中,探究发现,三角形的面积、边、角之间存在一定的数量关系,下面是她的学习笔记.请仔细阅读下列材料并完成相应的任务.
【阅读材料】:在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9c1e84aaa7e1b5c1283075b36c72fb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/718b5b48053888ab3b234b8cb56a0fc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5cbff84327e964f912a54032e76ccc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0e5738c6e0568f3678be0753a6d20d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d100b261160fa545b9429333a8d1c0.png)
同理可得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07127e5cbeab586bd7ab9172b4946200.png)
即:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd5eb951a762285cdbbb12b6434deabc.png)
由以上推理得结论①:三角形的面积等于两边及其夹角正弦积的一半.
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d822d72409e062de522c2c4e7ba89b52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a7aa99027d5e702b3f320487d12f020.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07a635b92109da0818e17f1f6fa030d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59f96747abf48e51b638bc0ff37bf501.png)
由以上推理得结论②:在一个三角形中,各边和它所对角的正弦的比值相等.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/facfe8a8-3cb2-4797-bef6-d74c03b53a13.png?resizew=144)
【理解应用】请你学习上述阅读材料解答以下问题:
如图,甲船以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/427cc3ae2dab5580fcb93eba22246595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a4c9b697e3df2b5469b71d3b5e47a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76c12e76fbd84eeec721386bd3b04cc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6093eebca8f3ff82ce9298feb197e955.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7ac5396c5ea442e0364b50c1db3d2da.png)
(2)求乙船航行的路程是多少海里(结果保留根号).
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适中
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【推荐1】如图1,已知四边形
是菱形,点E,F在对角线
上,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/7/c32fdf58-372a-49f4-8ce0-e1129ec26138.png?resizew=311)
(1)求证:
;
(2)如图2,若
,点E为
的中点,连接
交
于点O,连接
并延长交
于点G,在不添加任何辅助线情况下,请直接写出图2中等于线段
的
倍的四条线段.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92034dd2bb9480b18709d01153467f8f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/7/c32fdf58-372a-49f4-8ce0-e1129ec26138.png?resizew=311)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef202bebb4e139f5e201d6adefdded4b.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d948920201faba1c086843c71a1ea7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.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/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
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|
适中
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【推荐2】如图
,分别是可活动的菱形和平行四边形学具.已知平行四边形较短的边的长度与菱形的边长相等.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/c67142a3-518e-4779-8ec5-8afbac9db02c.png?resizew=357)
(1)将菱形的一边与平行四边形的较短边重合,摆拼成如图
所示的图形,
经过点
,连接
交
于点
.求证:点
是
的中点;
(2)如图
,在(1)的条件下,当
时,延长
,
交于点
,请探究
,
之间的数量关系,并给出证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/c67142a3-518e-4779-8ec5-8afbac9db02c.png?resizew=357)
(1)将菱形的一边与平行四边形的较短边重合,摆拼成如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce1132157a33c82610c2d5035493d024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(2)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14c89f9fb5d1a84be8aee78dca23090d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c4c865445dda4a59b6d5cb18fd74404.png)
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