I had a meeting this morning, so I showed up at the theater set build about 10:30   They were discussing how to make one of the circular cutouts for a riser.   Mind you, there was a HS math teacher, a math major (the shop manager), and a high school kid all trying to figure out how to mark out this circle.   They'd determined that the radius was 17+ feet and the arc was about 12' long, that was quite impossible to so in this shop laden with parts and wood.  The shop manager was trying to lay out some plastic hose to do it.    I told him "there is a better way," and asked him to look up an article that I'd written a few years ago.   He (and the math teacher whose current curriculum included straightedge and compass construction)  were surprised it worked but were amazed at how simple it was.  The last method here

 Maybe need to save this in woodworking tips. Thanks Keith.

A small nail (or thumbtack), a length of string cut to the length of the radius (plus enough to tie around the nail and a pencil). Draw the string taut and use the pencil to draw a perfect circle on the wood.

I don't like to math.... so I find ways to work less-smarter rather than harder LOL

2 hours ago, MaDeuce said:

A small nail (or thumbtack), a length of string cut to the length of the radius (plus enough to tie around the nail and a pencil). Draw the string taut and use the pencil to draw a perfect circle on the wood.

Only problem was the 17' diameter and 12' wide piece to cut exceeded the capacity of the floor space, plus finding exactly where the center would be that far away from the  pieces to be cut would be problematic.    We did use that technique to cut some 4' semi-circles.