∠ADB=180°—∠CDE-∠ADE=180°—∠CDE-∠AED,
180°—∠BAD—∠ABD=180°—∠CDE-∠AED,
180°—∠BAD—∠ABD=180°—∠CDE—∠CDE—∠ACB,
180°—∠BAD—∠ABD=180°—∠CDE—∠CDE—∠ABC,
所以180°—∠BAD—∠ABD=180°—2∠CDE—∠ABD
所以最后得出∠BAD=2∠CDE 手打得很辛苦,思路已经出来了 ,你自己理一理,因为数学具体的解题步骤我也已经忘得差不多了,求采纳
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