如图,O是直线AB上的一点,∠AOE=∠FOD=90°,OB平分∠COD,且∠BOC=28°.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/5f3befd7-6789-4eb9-b733-43406419dd63.png?resizew=138)
(1)求∠DOE和∠BOF的度数;
(2)求∠COE+∠DOE的度数.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/5f3befd7-6789-4eb9-b733-43406419dd63.png?resizew=138)
(1)求∠DOE和∠BOF的度数;
(2)求∠COE+∠DOE的度数.
20-21七年级下·山东聊城·期末 查看更多[3]
山东省聊城市东昌府区2020-2021学年七年级下学期期末数学试题山东省菏泽市定陶区2021-2022学年七年级下学期期末数学试题(已下线)第四章 基本平面图形 单元检测卷(A卷)-2022-2023学年七年级数学上册《同步考点解读·专题训练》(北师大版)
更新时间:2021-08-25 20:21:36
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解答题-问答题
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【推荐1】如图,直线
和
相交于点O,
,垂足为O,
平分
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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解答题-证明题
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【推荐2】将下面的推理过程及依据补充完整:
已知:如图,
平分
,
,求证:
平分
.
证明:∵
平分
(已知),
∴
① ,
∵
(已知),
∴
② (③ ),
∴
(等量代换),
∵
(已知),
∴④
(⑤ )
(⑥ ).
∴⑦
⑧ (等量代换),
∴
平分
.
已知:如图,
![](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/ecb7b211e8f3d4198c9d7203b80b8b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6beda2518cf76da94d7ec9a813dcfa82.png)
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证明:∵
![](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/386cda9f96731510d52ec18199e18286.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95cc39bd5f811ee710c8a9fb73d57791.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/386cda9f96731510d52ec18199e18286.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10e6203eae135b8a2b76a48f9711eef7.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75d2e5e5ec3caea31e3928183eebbc2b.png)
∴④
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∴⑦
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6706fe00b4e231e62d9ecbec567d526b.png)
∴
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解答题-证明题
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【推荐2】如图,已知
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