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等腰三角形ABC中,AB=AC,D为CB延长线上一点,E为BC延长线上点 ,且满足AB的平方=DB乘CE
(1):试猜想△ABC与△EAC相似吗?为什么?
(2):若∠BAC=40°,求∠DAE的度数.
人气:201 ℃ 时间:2019-08-18 05:58:07
解答
(1)△ABC∽△EAC∵AB^2=BD*CE,AB =AC ∴AB /CE=BD/AC∵AB =AC ∴∠ABC =∠ACB∴∠ABD=∠ACE∴△ABC∽△EAC(2)∵AB =AC ,∠BAC =40°∴∠ABC =70°∵△ABC∽△EAC∴∠D =∠CAE ∵∠D +∠DAB=∠ABC =70°∴∠DAE =40...
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