< I'm afraid the golden rectangle snap won't be ready for the next beta.
No problemo there are some Phicalculators on the Web :)
This one is some design :)
http://www.thismanslife.co.uk/main.asp?contentid=phiculator

But in some beta later....:)

If Arc Middle don't arrive in the next release...
Here a little method for remplace it :)
All construction lines will be disapear when a click release will be made!
So use the Point "C" before it flies away :D