如图,△ABC为等边三角形.O为BC的中垂线AH上的动点,⊙O经过B,C两点,D为弧上一点,D,A两点在BC边异侧,连接AD,BD,CD.
![](https://img.xkw.com/dksih/QBM/2015/9/24/1573915818319872/1573915824709632/STEM/aee0464420754e09b761e0e9176f02a7.png)
(1)如图1,若⊙O经过点A,求证:BD+CD=AD;
(2)如图2,圆心O在BD上,若∠BAD=45°;求∠ADB的度数;
(3)如图3,若AH=OH,求证:BD2+CD2=AD2.
![](https://img.xkw.com/dksih/QBM/2015/9/24/1573915818319872/1573915824709632/STEM/aee0464420754e09b761e0e9176f02a7.png)
(1)如图1,若⊙O经过点A,求证:BD+CD=AD;
(2)如图2,圆心O在BD上,若∠BAD=45°;求∠ADB的度数;
(3)如图3,若AH=OH,求证:BD2+CD2=AD2.
更新时间:2016-12-06 02:42:51
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【知识点】 圆与三角形的综合(圆的综合问题)
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的长度;
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