1 . 综合与实践∶
【问题背景】鲜艳的中华人民共和国国旗始终是当代中华儿女永不褪色的信仰,国旗上的每颗星都是标准五角星,为了增强学生的国家荣誉感、民族自豪感等,数学老师组织学生对五角星进行了较深入的研究,其中智慧数学小组发现国旗上五角星的五个角都是顶角为
的等腰三角形,对此三角形产生了极大的兴趣并展开探究.
【探究发现】如图 1,在
中, ![](https://staticzujuan.xkw.com/quesimg/Upload/formula/093c6b5aeaa7e581ad4345e137c24c92.png)
(1)操作发现:将
折叠,使边
落在边
上,点C的对应点是点E,折痕交
于点 D,连接
,则
°,设
, 那么
(用含x的式子表示);
(2)进一步探究发现:顶角为
的等腰三角形的底与腰的比值为
这个比值被称为黄金比.请在 (1)的条件下证明:
.
【拓展应用】当等腰三角形的底与腰的比等于黄金比时,这个三角形叫做黄金三角形.例如,图 1 中的
是黄金三角形.
(3)如图2, 在菱形
中,
.求这个菱形较长对角线的长.
【问题背景】鲜艳的中华人民共和国国旗始终是当代中华儿女永不褪色的信仰,国旗上的每颗星都是标准五角星,为了增强学生的国家荣誉感、民族自豪感等,数学老师组织学生对五角星进行了较深入的研究,其中智慧数学小组发现国旗上五角星的五个角都是顶角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7b398c95494eddc79939f16e66cf4da.png)
【探究发现】如图 1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/093c6b5aeaa7e581ad4345e137c24c92.png)
(1)操作发现:将
![](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/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1b48221615e7f6d622b32fac9b069c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86bcfb91bf2911f80be6a2dcf42ae3aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/502a7344464cfa21689eec94792fe51a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d57b4243fa7f6f9c73d11f3123c42ddb.png)
(2)进一步探究发现:顶角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7b398c95494eddc79939f16e66cf4da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c942a6ae83c85989833ca0ec3cb779ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5156adc8c4bbbebb15d992a26a529484.png)
【拓展应用】当等腰三角形的底与腰的比等于黄金比时,这个三角形叫做黄金三角形.例如,图 1 中的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(3)如图2, 在菱形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/168a096c7d47ed44bb5c2688d209c6fc.png)
您最近一年使用:0次
2 . 【感知】(1)如图①,在
中,
,
是角平分线,
是高,
相交于点
.若
,则
°,
°.
【探究】(2)如图①,在
中,
,
是角平分线,
是高,
相交于点
.求证:
.
【拓展】(3)如图②,在
中,
,
是
边上的高,若
的外角
的平分线交
的延长线于点
,其反向延长线与
边的延长线交于点
,若
,则
的大小为 (用含
的代数式表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bb281d219961d3d3824d3bbfeaaf1dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/640e9e7c56e8eeda044fb55396088816.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d060b523623f7dd4ba63470ceb4ca0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a911ba9342ec2d17b55839cb8838d9f.png)
【探究】(2)如图①,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bb281d219961d3d3824d3bbfeaaf1dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7480ab1a16ccbd8f28166cf6b97aad54.png)
【拓展】(3)如图②,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d34b2c6c1379ea4968962e96eba6cd18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.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/6988b81937a2b98659c359d9ed686146.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adcae9d00980803e5955228d1e217abe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
您最近一年使用:0次
3 . 数形结合思想是初中数学学习中很重要的一种思维方法,“数”的精确描述与“形”的直观刻画,使代数问题与几何问题相互转化.“以形释数”是利用数形结合思想解决代数问题的一种体现,做整式的乘法运算时,利用几何直观的面积法获取结论,在整式运算中时常运用.
【问题探究】
探究1:如图1所示,大正方形的边长是
,它是由两个小正方形和两个长方形组成,所以大正方形的面积等于这四个图形的面积之和.根据等积法,我们可以得出结论:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/375d440fa0c1da0617388f0fc270542c.png)
探究2:请你根据探究1所使用的等积法,从图2中探究出
的结果.
(1)
;
【应用结论】
(2)已知
,
,分别求
与
的值;
【变式拓展】
(3)因式分解:
【问题探究】
探究1:如图1所示,大正方形的边长是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0034de31c6d9f4412cf54a01160c3573.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/375d440fa0c1da0617388f0fc270542c.png)
探究2:请你根据探究1所使用的等积法,从图2中探究出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5960b5ba8bc7d4d138f597bc64db614.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5aa563636a6590ca0e84cd20be9ae901.png)
【应用结论】
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e56f4504e0f80fd031c8b5f41832e03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c85d2a16dc4d2f4a488129d8243f15f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bafa8d972ced9eecf153f7bf64235a57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1c2a9a6c0eab1d669a86789312eb5d4.png)
【变式拓展】
(3)因式分解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f91c2dc9105c8a2167153de11cf0d4b.png)
您最近一年使用:0次
4 . 【感知】(1)如图1,
为
之间的一点,连接
,得到
.求证:
.
证明:如图①,过点
作
.
(已知),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d518dc5553bc24f8b58371097d628d2.png)
______(______)
(______)
(等式性质),
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1b77c2dbc7ca2e1c76c1d4e0ac2276f.png)
(2)【类比探究】请你利用上述【感知】中的结论进行,证明下面的问题:
如图2,已知
,点
在
上,
,
请你说明
;
(3)【拓展延伸】如图3,
平分
平分
.若
,请直接写出
的度数为______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a2729b8b1abcc19b12ce78db3141004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5c4cd264c97c1f261229925cc5a6761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b60b1106dab7a5191351381230d90ea8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb3de20ba8bda63c650ef571be155702.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9431abc6d126074531bc93f8e9e75726.png)
证明:如图①,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c197d8b99f2eb7477947e53461b5d548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d46d51edf02633ff4c3b9b2c7dc4fea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d518dc5553bc24f8b58371097d628d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32601eb579a10b869df48b6c5a626088.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c568a9f5c12bb1cf7aa811ecb2cf33cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1b77c2dbc7ca2e1c76c1d4e0ac2276f.png)
(2)【类比探究】请你利用上述【感知】中的结论进行,证明下面的问题:
如图2,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c2cd6207884eb558aea47782314776e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f54aa7d03a3f2b5f2a3b468547e248c.png)
请你说明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb948c23dc9b9073a71ec07494158ff3.png)
(3)【拓展延伸】如图3,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b61f3022554c9fc6c1074f23b30ac8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a28767bd3c4ad810e5b9f78acb2a049.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60c7e98e116cfeb3ea600ee93398e455.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36719f1e764ee0e719b65c49fae84677.png)
您最近一年使用:0次
名校
5 . 【阅读思考】如图①,已知
,探究
、
、
之间关系,小明添加了一条辅助线.解决了这道题.得到的结果是
.
证明过程如下:
如图①,过点
作![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe9f641563e8533a5bb39188aa7cc182.png)
.
,
,
,
,即
.
,求
的度数;
(2)【拓展探索】如图③,已知
,点
在点
的右侧,
,
平分
,
平分
,
,
所在的直线交于点
,点
在直线
与
之间,点
在点
的右侧,且
,
,若
,则
度数为 ?(用含
的代数式表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03733d1465d041a6d6da32bf91a7cff8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b871a762469393cdd22f15aa49ebb8f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db866ecc0c098bfc32ec8a43b65bdd58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1f954d2d6ce1c935fa6c9a7f9de6ad3.png)
证明过程如下:
如图①,过点
![](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/5a772b41de6cab4c2acca5bf9b865833.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32bf0ea5fbeec01b96f25a329f63d6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5a897346cb5e3c10268c41f112997f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24592bfd5ab683f124ce1b3849659812.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f961b1b5391ed6c272f7a22fda3fd1c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1f954d2d6ce1c935fa6c9a7f9de6ad3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03733d1465d041a6d6da32bf91a7cff8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ded11f1d465cee30733c43bbd332bbfd.png)
(2)【拓展探索】如图③,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0b17b275d892a076f768524c400a6f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/9d78abbad68bbbf12af10cd40ef4c353.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/b8ce3618abaf1907e7661e4204047f4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4652f95f3a388706906bc85f53f8db1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/074d1bdb0a6c414fa3d8b8b316e2e9b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb3de20ba8bda63c650ef571be155702.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
2024-03-12更新
|
207次组卷
|
4卷引用:广西壮族自治区南宁市天桃实验学校2023-2024年七年级下学期3月月考数学试题
6 . [学习探究]
数学中,常对同一个量(图形的面积、点的个数、三角形的内角和等)用两种不同的方法计算,从而建立相等关系,我们把这一思想称为“算两次”,“算两次”也称做富比尼原理,是一种重要的数学方法.
如图1,两个直角边分别为
,斜边长为
的直角三角形和一个两条直角边都是
的直角三角形拼成一个梯形.
解:有三个直角三角形其面积分别为
,直角梯形的面积为
.由图形可知:
.整理得
,
.
.
故结论为:如果用
和
分别表示直角三角形的两直角边长和斜边,那么
.
[类比尝试]
(1)如图2,在
的正方形网格中,每个小正方形的边长均为1,点
都在格点上,若
是
的边
上的高,求:
①
的面积;
②
的长.
[拓展探究]
(2)如图3,在平面直角坐标系中,直线
与
轴、
轴分别交于点
和
,直线
经过坐标原点,且
,垂足为
,求:
①
点和
点的坐标.
②点
到
轴的距离.
数学中,常对同一个量(图形的面积、点的个数、三角形的内角和等)用两种不同的方法计算,从而建立相等关系,我们把这一思想称为“算两次”,“算两次”也称做富比尼原理,是一种重要的数学方法.
如图1,两个直角边分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/663a61ad241d5d874c9a9362f0ee917c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
解:有三个直角三角形其面积分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f7b2ec9c00f8818aa0f7ebcf6420fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0378931b8806153b8eb6752f9fba87c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2439df6d11ddc5c5a9d253d8cc14e9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad8b29da4732a254e860c383819ae5fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4cc749848ff381f793656f4a01e2a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f28ce1d79263c8c713ac4181b4077b80.png)
故结论为:如果用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/663a61ad241d5d874c9a9362f0ee917c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3133ef62aad6bdd6637140620f068fad.png)
[类比尝试]
(1)如图2,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fb9d60d456560e9bac66c8b20c49bb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38335830b93ac4d99c28a8e209eecb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
[拓展探究]
(2)如图3,在平面直角坐标系中,直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ddb259ccc3685a453857eba7ad499b8.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/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a23dff476ddce008f686a26be4adbef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
②点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/3/c4689a33-6860-4f5c-b927-b5bab37ca8ea.png?resizew=344)
您最近一年使用:0次
7 . 【问题情境】
利用角平分线构造全等三角形是常用的方法,如图1,
平分
.点
为
上一点,过点A作
,垂足为C,延长
交
于点B,可根据______证明
,则
,
(即点C为
的中点).
【类比解答】
如图2,在
中,
平分
,
于E,若
,
,通过上述构造全等的办法,可求得
______.
【拓展延伸】
(1)如图3,
中,
,
,
平分
,
,垂足E在
的延长线上,试探究
和
的数量关系,并证明你的结论.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/4/e6116658-178c-4e35-bcb4-8f205f15c939.png?resizew=440)
(2)如图4,
中,
,
,点D在线段
上,
,
,垂足为
,
与
相交于点F.线段
与
的数量关系为______.(直接写出)
利用角平分线构造全等三角形是常用的方法,如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0101a7b5c8a4aed0de2af363792e39a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27935c1ef4df2d52ac697678a3c8f39d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18a2fe360dbaf805c6b8bff7b07c1dd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/075bc6df108c9c2b3b5ac46bca7c8d3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03ae5640206c24e99d0c2584e632a46b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/129f2a8a3a38ec4119d5e1016dd04f1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
【类比解答】
如图2,在
![](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/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4611ceb2a28f7a7e4d24266d7f99b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e79fff206344e255d7aa364e78e35152.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2507d3a2e1344315f80237c91e5c4c34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32e910dce5a57ff0d917e0b4dd620214.png)
【拓展延伸】
(1)如图3,
![](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/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b937442ad4cc480adc11bb143559454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0213c5787a5a6b38d11bceca5567f67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/4/e6116658-178c-4e35-bcb4-8f205f15c939.png?resizew=440)
(2)如图4,
![](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/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65dfd32cc6ff4d10f7992d84915043f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c182a9d9fd0a7023b710cd671d9468e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0213c5787a5a6b38d11bceca5567f67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faee0268e5ede6318697e5a8509dd6f7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/4/a1662243-d315-4164-882f-298f7a785174.png?resizew=153)
您最近一年使用:0次
2024-01-29更新
|
67次组卷
|
2卷引用:河北省保定市唐县2023-2024学年八年级上学期期末数学试题
8 . 问题情景:
数学活动课上,小明发现右图中蕴含着一个数学模型.
如图①,若
,点
在
,
之间,连接
,
,则
,请说明理由.
拓展探究:
小明还发现若改变点
的位置,如图②,若点
在
上方,连接
,
,则
,
,
依然存在一定的数量关系,请认真思考后得出结论,并进行证明.
问题解决:
如图③,
,点
在射线
上运动,
,
.请直接写出
的度数.
数学活动课上,小明发现右图中蕴含着一个数学模型.
如图①,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.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/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd6d9ef732deabacced5b48b2e32cf49.png)
拓展探究:
小明还发现若改变点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb3de20ba8bda63c650ef571be155702.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
问题解决:
如图③,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4769498f7869c140346fd9c0f54f8e0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5d4d180b7fc190f6ea88a5f188e2c23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a71e8a816d9ef65d4bffd81fd53216.png)
您最近一年使用:0次
2024-01-21更新
|
157次组卷
|
2卷引用:河南省开封市2023-2024学年七年级上学期期末数学试题
名校
9 . 综合与探究
【操作探索】
在生活中,我们常用实物体验图形变换的过程.小颖同学利用一块风筝纸片完成了如下的操作:
如图1,已知四边形
,
,
.
(1)操作一:沿
所在的直线对折,如图1.你认为左右两侧对折后能完全重合吗?并说明理由;
(2)操作二:对折后,将风筝纸片剪成两个三角形(
和
),摆成如图2所示的图形,
与
相交于点
,
与
相交于点
.试说明
.
【应用拓展】
(3)如图3,在
中,
,
,点
在边
上,
,点
,
在线段
上,
,
,若
的面积为24,求
与
的面积之和.
【操作探索】
在生活中,我们常用实物体验图形变换的过程.小颖同学利用一块风筝纸片完成了如下的操作:
如图1,已知四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/520f8abda6a85e7ef6f281fc2df853fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/532aece6cfd67e2a97977eed978dbf2b.png)
(1)操作一:沿
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
(2)操作二:对折后,将风筝纸片剪成两个三角形(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6829c6214e60edbfbf1e31601c6bcb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9b123ae31090740589ba27a846620b5.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/e8ba89e83329983cfadbfcdda151aaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f805768a5ffaf8bdfa4bc3b680aafdc9.png)
【应用拓展】
(3)如图3,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/f2da1d50433aecf541991fd0f01773cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a7e75d7342e6f087370d09181b17a4e.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcff853a0873d0a6b93e4f90725752a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/456e0f77d83975fdbdb60b499cb5b521.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5df7626240940eb340420a605e95aeee.png)
您最近一年使用:0次
10 . 观察图①,用等式表示图中图形的面积的运算为__________________________.
【类比探究】观察图②,用等式表示图中阴影部分图形的面积和为_____________.
【应用】(1)根据图②所得的公式,若
,则
_____________.
(2)若x满足
,求
的值.
【拓展】如图③,某学校有一块梯形空地
于点
.该校计划在
和
区域内种花,在
和
的区域内种草.经测量种花区域的面积和为
,
,直接写出种草区域的面积和.
【类比探究】观察图②,用等式表示图中阴影部分图形的面积和为_____________.
【应用】(1)根据图②所得的公式,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cd863a46ad3c3aca19fb18553823985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2b1b96f5050de3bc7ae53c7bf0c21e8.png)
(2)若x满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65c6552a78f017cdc62eac72d2f75a73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ed1131957df727f591a1da261476d68.png)
【拓展】如图③,某学校有一块梯形空地
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e31f5aa223abfaf6345219bc73935e4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7410e861352b0c37b3c507611dfb4a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c771a4feb150ad9cff8d70431c97eb17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2657e02314469ad2b13d31dce41b4343.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ff878bdf790d8d13a70507e96e1135f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f186ea827f7becafd1ac4955e22c6812.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/18/ff895608-a81b-4012-b5f9-688688c8d46e.png?resizew=610)
您最近一年使用:0次