1 . 已知一个三角形的三边长为4,7,x,则x的取值范围是_______ .
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2 . 以下列各组线段长为边,能构成三角形的是( )
A.![]() | B.![]() |
C.![]() | D.![]() |
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3 . 已知等腰三角形的两边长分别为4和8,则它的周长为( )
A.10 | B.16 | C.20 | D.16或20 |
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4 . 八年级一班数学兴趣小组在一次活动中进行了探究试验活动,请你和他们一起活动吧.
【阅读理解】如图1,在
中,若
,
.求
边上的中线
的取值范围.小聪同学是这样思考的:延长
至
,使
,连接
.利用
与
全等将边
转化到
,在
中利用三角形三边关系即可求出中线
的取值范围.在这个过程中小聪同学证
与
全等的判定方法是:__________;中线
的取值范围是__________.
【阅读感悟】解题时,条件中若出现“中点”“中线”字样,可以考虑延长中线构造全等三角形,把分散的已知条件和所求证的结论转化到同一个三角形中.
【理解与应用】如图2,在
中,
,点
是
的中点,点
在
边上,点
在
边上,若
.证明:
.
【问题解决】如图3,在
中,点
是
的中点,
,
,其中
,连接
,探索
与
的关系,并说明理由.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/14/c83c6716-9915-44eb-a470-ac229a0803aa.png?resizew=460)
【阅读理解】如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07140f277a35733d8c97577ccdd4e3ab.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/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63f94cb32b388456ab9203e8d8b5309e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecd75c2244c18120b8fc35d5d309ab66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbfa1a2af7e38d33634c462300df381f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecd75c2244c18120b8fc35d5d309ab66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
【阅读感悟】解题时,条件中若出现“中点”“中线”字样,可以考虑延长中线构造全等三角形,把分散的已知条件和所求证的结论转化到同一个三角形中.
【理解与应用】如图2,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.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/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e47f2874795e9df280e3e0bec171358e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e17c1c2b2b0a45b267e3a33d169737e.png)
【问题解决】如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/905ce72c0bf1b4ec192e86744b6eee17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01f8ddd2dacc842ddb8002f1e6c3b65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce5e3c181434be67afb779f5e0e05c3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
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5 . 已知三角形的两边长分别是3和7,则这个三角形第三边长不可能是( )
A.9 | B.7 | C.5 | D.3 |
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6 . 下列每组数分别是三根小木棒的长度,能摆成三角形的是( )
A.![]() ![]() ![]() | B.![]() ![]() ![]() |
C.![]() ![]() ![]() | D.![]() ![]() ![]() |
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2023-11-01更新
|
47次组卷
|
2卷引用:云南省昭通市昭阳区昭阳区第一中学等校联考2023-2024学年八年级上学期10月月考数学试题
7 . 已知
为
的三边长.
(1)化简:
;
(2)若
,
,
为偶数,判断
的形状.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bba1e7a657ed134e68efd159b606620f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(1)化简:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d72367aa55f93039afbbbb46d5aba6fd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82986ab38a4ae58593191ccae2a44f62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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8 . 已知a、b、c为三角形的三边,则
化简后的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2648c6b0ae4ea9359c2ed8fa54a96ca8.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2023-10-30更新
|
126次组卷
|
2卷引用:云南省昭通市巧家县大寨中学2023-2024学年八年级上学期10月月考数学试题
名校
9 . 新定义:我们把两个面积相等但不全等的三角形叫做偏等积三角形.
初步尝试
(1)如图1,在
中,
为
上一点,当
的长为 时,
与
为偏等积三角形.
理解运用
(2)如图2,
与
为偏等积三角形,
且线段
的长度为正整数,过点
作
平行
,交
的延长线于点
,求
的长.
综合应用
(3)如图3,已知四边形
是等腰直角三角形,
,则
与
是偏等积三角形吗?请说明理由.
初步尝试
(1)如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39cabd1160b393044bca6c86dff927f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a855335176fc36a15017f50a8561348.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/403d74859e7b8b4cebf40add6e92b0f8.png)
理解运用
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af2f502e92e09d86ecbbf93777781e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
综合应用
(3)如图3,已知四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1597c4a55faaf0496e21cd21a3dab370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9a13231a1ed5e8a8750368f1e51255d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbfa1a2af7e38d33634c462300df381f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/28/19c836b8-af90-4944-9a11-2944861e5b5e.png?resizew=483)
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2023-10-27更新
|
216次组卷
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5卷引用:云南省德宏傣族景颇族自治州2023-2024学年八年级上学期期末数学试题
名校
10 . 已知
是
的三边,
,
,
为整数.则
的周长为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88f2599ca8b6b683e57a82699c8b1ebb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b550ee821ee1838384835e81fc34b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcdb7a488910743dc5c63afb394b87e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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