Designing parts of circles with uncommon measurements?
Take the 45° and add the 15° to either side. 15 and 45 are 60° but with the added 15° you wind up with 75° arc which is not common.
Draftsmen would use a protractor, a quilter might not.
I could see using the 45° as a main template in a dark color and the 2 15° as a lighter color making a different looking flower.
That might not be so easy to measure.
I could have some fun using something like that to lay out quilting, too. All the unusual with half the work.