## [數學]求∠BCA+∠BDA+∠BEA+∠BFA

Raceleader

### Re: [數學]求∠BCA+∠BDA+∠BEA+∠BFA

Raceleader 寫到:圖中，BCDEF是一直線，∠ABF=90°，AB=EF=1，BC=3，CD=DE=2，求∠BCA+∠BDA+∠BEA+∠BFA。

No one know

Raceleader

let me try to add a rectangle to it, i think it works

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I tried rotate them, but failed

Raceleader

i've seen a similar question, use add rectangle

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It has written in another message page

Raceleader

But no challenge

Raceleader

scsnake

Can you do this?

Raceleader

chiny

Which one is the required figure?

Raceleader

Right!!

FAE+BAC=90-EAC=ECA=RNP
HGI+JGK=90-KGI=KIG=RNM
RNP+RNM=90-PNO=45
(以上單位：degree)

scsnake

scsnake 寫到:這題不叫challenge，這叫無聊∼

You think this Q is nonsense.

Raceleader

yptsoi

scsnake 寫到:Right!!

FAE+BAC=90-EAC=ECA=RNP
HGI+JGK=90-KGI=KIG=RNM
RNP+RNM=90-PNO=45
(以上單位：degree)

kevin

These questions are very simple.
You can use sin, cos and tan to solve these questions.

lckjackie

lckjackie 寫到:These questions are very simple.
You can use sin, cos and tan to solve these questions.

Yes , i totally agree with you. But please see th question clearly .

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E.T