Need Help With Math B Regents June 2005

I'm currently reviewing for the Math B regents and I have some trouble with 5 questions I looke up the answers online but i still need help showing the work to arrive to the answers. Here is the link to the the answers:http://www.nysedregents.org/testing/mathre/b-key605.pdf

And here is the link to the questions:http://www.nysedregents.org/testing/mathre/b605.pdf

These are the question i need help showing work for. 23,29,31,33, and 34.

In 34 i got the second part i just need help figuring out the diameter of the circle.