小知识:如图,我们称两臂长度相等(即
)的圆规为等臂圆规. 当等臂圆规的两脚摆放在一条直线上时,若张角
,则底角
.
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/f8aa11aca6b14d2f909d52425c38f64b.png?resizew=83)
请运用上述知识解决问题:
如图,
个相同规格的等臂圆规的两脚依次摆放在同一条直线上,其张角度数变化如下:
,
,
,
,…![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/7c0f6d47b8a4480c82b7182fa506c62b.png?resizew=398)
(1)、①由题意可得
= º;
②若
平分
,则
= º;
(2)、
= º(用含
的代数式表示);
(3)、当
时,设
的度数为
,
的角平分线
与
构成的角的度数为
,那么
与
之间的等量关系是 ,请说明理由. (提示:可以借助下面的局部示意图)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d89ba4036a5d18ec4abed44d7fd8e89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99f9b188c0b6bd2350ee396bf0a20b2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65652ca101c529234a4f1553ceb4e71c.png)
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/f8aa11aca6b14d2f909d52425c38f64b.png?resizew=83)
请运用上述知识解决问题:
如图,
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/0da61871e60f4ff3a957d763db1bf0d8.png?resizew=13)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9546eafd5fbba32abac2d6ba0614c276.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07446afb5b9c8f0c6e79cdcc64720f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b1680e54c0ea928aa165f07c5fddcfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f87a386e73f4baa6377d084b5c8af56.png)
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/7c0f6d47b8a4480c82b7182fa506c62b.png?resizew=398)
(1)、①由题意可得
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/348f136b273a41d88b9f51e169259055.png?resizew=61)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c2cc110e46ae4b3432814810e28bcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635182594a817409f67a7332590fb717.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fdecdb3fc5168f2f96388163631ad5f.png)
(2)、
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29d5fd90f2a4faa3ad8f4cecc09a460d.png)
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/0da61871e60f4ff3a957d763db1bf0d8.png?resizew=13)
(3)、当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bcfc48f9bc23cc43085bdb910e7a136.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c236c705b7c9116aa718372c87a7fc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8621dfd5c12ebdbc1216ad65fb2002e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f290e3e451d234086ceca4c07f01c07f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eceaaffe30941af4c7cb9fb9f1f608d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://img.xkw.com/dksih/QBM/2016/4/29/1574199472635904/1574199479173120/STEM/a530969d9d4f4d70b51b7fa65a16352b.png?resizew=175)
15-16七年级上·广西崇左·阶段练习 查看更多[3]
2015-2016学年广西崇左市大新县全茗中学七年级上第一次月考数学卷湖北省黄石市黄石港区2018-2019学年上学期七年级期末数学试题(已下线)【新东方】【2021.6.8】【TZ】【初一下】【数学】【补00002】
更新时间:2016-12-06 12:19:57
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】如图是由一些火柴搭成的图案:
![](https://img.xkw.com/dksih/QBM/2018/5/12/1943788392423424/1949298852945920/STEM/fa2ac3f4479640cead1aa995ce5bf4f4.png?resizew=269)
(1)观察图案的规律,第4个图案需 根火柴;
(2)照此规律,第2 016个图案需要的火柴为多少根?
![](https://img.xkw.com/dksih/QBM/2018/5/12/1943788392423424/1949298852945920/STEM/fa2ac3f4479640cead1aa995ce5bf4f4.png?resizew=269)
(1)观察图案的规律,第4个图案需 根火柴;
(2)照此规律,第2 016个图案需要的火柴为多少根?
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
【推荐2】【观察思考】
(1)第
个图案中黑色方块的个数为___________,黑、白两种方块的总个数为___________.
(2)第
个图案中黑色方块的个数为___________,黑、白两种方块的总个数为___________.(用含
的代数式表示)
【规律应用】
(3)白色方块的个数可能比黑色方块的个数多
吗?若能,求出是第几个图案;若不能,请说明理由.
(1)第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
(2)第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
【规律应用】
(3)白色方块的个数可能比黑色方块的个数多
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8e8936c9fe1e81726455908657a29fc.png)
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
【推荐3】我国著名的数学家华罗庚曾说过:“数形结合百般好,隔裂分家万事非”.
【I】如图,请你用“数形结合”的思想.
![](https://img.xkw.com/dksih/QBM/2022/11/23/3115945663897600/3122790358712320/STEM/e34ff81c64b547a2bb984bab85528fc6.png?resizew=107)
(1)求
的值为 ;
(2)请你利用(1)
结论,求下列各式的值:
①
= ;
②计算:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b1a211963082514980a5da2e33575d7.png)
【II】将若干个同样大小的小长方形纸片拼成如图形状的大长方形(小长方形纸片宽为a,长为b),请你仔细观察图形,解答下列问题:
(3)a和b之间的关系满足 .
(4)图中阴影部分的面积与大长方形面积的比值是 .
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/020b86f2-f32d-4b16-a8fe-c7c4e2b03024.png?resizew=286)
(5)请你仔细观察图中的一个阴影部分,根据面积的不同表示方法,请你写出
与
,
三个代数式之间的等量关系 ;
(6)应用:根据探索中的等量关系,解决如下问题:
,
,求
的值.
【I】如图,请你用“数形结合”的思想.
![](https://img.xkw.com/dksih/QBM/2022/11/23/3115945663897600/3122790358712320/STEM/e34ff81c64b547a2bb984bab85528fc6.png?resizew=107)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9572df7e1613f3e5990f093d17fa5e06.png)
(2)请你利用(1)
![](https://img.xkw.com/dksih/QBM/2022/11/23/3115945663897600/3122790358712320/STEM/c162228f22224bf29577169c8e25eb9f.png?resizew=14)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd1229b53d1ea799f2fe26919b81439f.png)
②计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b1a211963082514980a5da2e33575d7.png)
【II】将若干个同样大小的小长方形纸片拼成如图形状的大长方形(小长方形纸片宽为a,长为b),请你仔细观察图形,解答下列问题:
(3)a和b之间的关系满足 .
(4)图中阴影部分的面积与大长方形面积的比值是 .
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/020b86f2-f32d-4b16-a8fe-c7c4e2b03024.png?resizew=286)
(5)请你仔细观察图中的一个阴影部分,根据面积的不同表示方法,请你写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f8aa85139befa047587acd0019806e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8644940585ce7d65e99a1f5672cdd195.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18f0281e6bbdbe08beeccb55adf84536.png)
(6)应用:根据探索中的等量关系,解决如下问题:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9caff846b9d2d4ea37b7df76719c68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf3f30d48c3ab531e3ab8455c5d1b293.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/059d6df06a5b85848dc4fa33327f8e07.png)
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
【推荐1】如图,O为直线AB上一点,∠AOC=50°20′,OD平分∠AOC,∠DOE=90°.
(1)求∠DOB的度数;
(2)请你通过计算说明OE是否平分∠COB.
(1)求∠DOB的度数;
(2)请你通过计算说明OE是否平分∠COB.
![](https://img.xkw.com/dksih/QBM/2019/4/17/2184318476779520/2184937946234880/STEM/c713b4987e47421386cca29f2ea17004.png?resizew=194)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐2】如图,∠AOB是平角,OD、OC、OE是三条射线,OD是∠AOC的平分线,请你补充一个条件,使∠DOE=90°,并说明你的理由.
![](https://img.xkw.com/dksih/QBM/2013/1/21/1573594173710336/1573594185711616/STEM/236ab67bc4614fa3af89a73aca0d0a53.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐3】如图1,点O为直线
上一点,过O点作射线
,使
,将一直角三角板的直角顶点放在点O处,一边
在射线
上,另一边
在直线
的下方.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/1/29521441-addc-4d68-8145-fa3ec888480e.png?resizew=369)
(1)如图2,将图1中的三角板绕点O逆时针方向旋转
至图2的位置,求
的度数;
(2)如图3,将图1中的三角板绕点O按每秒
的速度逆时针方向旋转α度(
).
①若经过t秒后线段
在
的内部,且
,求t的值;
②在三角板转动时,射线
同时绕点O以每秒
的速度按顺时针方向旋转,当三角板停止转动时,射线
也停止转动.经过t秒直线
恰好平分
,请直接写出 满足条件的t的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a535052f3a139a91d46ec40ff72f2e14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e9f7d1272b7344346b58b660aa260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/1/29521441-addc-4d68-8145-fa3ec888480e.png?resizew=369)
(1)如图2,将图1中的三角板绕点O逆时针方向旋转
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bd0dc942dc5a587e3c638df0d42c76b.png)
(2)如图3,将图1中的三角板绕点O按每秒
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdb0aa8a61380228e285f3b5c7b74c47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a1ff061891062dba42947d19281cd4f.png)
①若经过t秒后线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e9f7d1272b7344346b58b660aa260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fed1f57a835af4e9022e27603d12d31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8764ece81ea864f9ce27a32e09a338.png)
②在三角板转动时,射线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb204f42d5fb6cd55050a18cca2804b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e9f7d1272b7344346b58b660aa260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fed1f57a835af4e9022e27603d12d31.png)
您最近一年使用:0次