Quilt in a day shows you how to do it with Eleanor Burns Egg Money Quilts.
You sew a certain number of 2 1/2 strips then lay her template over the top and cut round it then you have your arc.
I have not explained this very well but go and look on www.quiltinaday.com and look for the videos for Egg Money Quilts and in there they will show you videos of all the quilts in the book. The book of that name comes with the templates I have just bought the book so can confirm that the cardboard templates are there.
Good luck.
Jenny