如图,在▱ABCD中,延长AB到点E,使BE=AB,DE交BC于点O,连接EC.
(1)求证:四边形BECD是平行四边形;
(2)若∠A=40°,当∠BOD等于多少度时四边形BECD是矩形,并说明理由.
(1)求证:四边形BECD是平行四边形;
(2)若∠A=40°,当∠BOD等于多少度时四边形BECD是矩形,并说明理由.
![](https://img.xkw.com/dksih/QBM/2021/7/26/2772314397892608/2786923293859840/STEM/0a5c836be3f941ce98296fc279d726e2.png?resizew=153)
更新时间:2021-08-15 21:52:52
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解答题-证明题
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【推荐1】如图,平行四边形
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/a264f41d-d95e-458f-88d5-56f83accd87c.png?resizew=144)
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【推荐2】如图,在平行四边形
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(1)你添加的条件是 ;
(2)根据你添加的条件,写出证明过程.
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