How to Calculate Forces in a Beam Using the Method of Sections

[Arty7]

IHi guys with part b of this question I am having trouble. I have cut it it at the specified members and used the top half. Now i take the moment at A to get the force in BC. (CW+)M@A=(6*3)+(6cos(30)*3)=0, But when you solve this it doesn't give you the answer its supposed to be, I am probably blind & missing something. Please check out the attachments i provided some more info on it.

Thankyou in Advance.

 

[SteamKing]

No attachments provided.

 

[Arty7]

Sorry man, its up now

 

[SteamKing]

Where do you get 30 degrees from? Check your triangles.