Given chord length c and segment height m (this is called a "sagitta"),
radius = (m^2 + (c^2)/4) / (2 m)
In OpenSCAD:
c=20;
m=5;
radius=(pow(m,2) + pow(c,2)/4)/(2*m);
https://softsolder.com/2013/08/02/making-finger-grip-dents-the-chord-equation
https://en.wikipedia.org/wiki/Circle#Sagitta
blogodex = {"idx": ["openSCAD", "circle"]};