Help with geometry proofs

[Sergey]

I need help with a few proofs, there are six problems in total, help with any/all of them is greatly appreciated. # 1, 2, and 5 stumped me the most. I've added the picture of the problems as an attachment but you can look at the image online as well.

I drew the pictures/wrote the givens and what needs to be proved.
http://img14.imageshack.us/img14/7230/geometryquestions.jpg

Standard statements/reasons table, except when it says that you need to indirectly prove it for #1.

Thank you very much for any/all help!

Attachment available at http://mathforum.org/kb/servlet/JiveServlet/download/128-1954393-6750129-559046/Geometry%20questions.JPG

[Ken Pledger]

> I need help with a few proofs ....
> http://img14.imageshack.us/img14/7230/geometryquestion
> s.jpg
> ....

First you need to explain what sort of theory or axioms underlie all this, because that determines what techniques can be used.

I can see how to do #1 directly, but the instruction "Prove indirectly" is quite puzzling. Also, ## 2, 3 and 4 need more information than the diagrams show. In #2 I guess AC is meant to be a diameter. In #3 you need some information about lengths or angles in those triangles. In #4 the rhombus has to be special in some way before you can prove it is a square. It would be best to post the _complete_ wording of the original questions, as the details do matter.

Ken Pledger.