maths trigonometry
2013-11-07 7:38 am
圖片參考：http://imgcld.yimg.com/8/n/HA00274964/o/20131106233309.jpg
could you please explain this question with steps? thanks!
回答 (1)
2013-11-07 7:50 am
✔ 最佳答案
(=^o^=)Yuki, nice question!!!
(1)
Note that AB // DC.
(2)
Then, you can know that △ABE ~ △DCE (AAA)
(3)
By similar triangle, you know that
BE : DE = AB : DC (this is what you are asked)
(4)
Note that tan φ = AB/BC
tan θ = DC / BC
(5)
Therefore,
BE : DE = AB : DC = AB/BC : DC/BC = tan φ : tan θ
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原文連結 [永久失效]:
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