intersection of any plane with surface with >1 points is a circle, sphere
Source: 1965-66 Germany R4 12.6 https://artofproblemsolving.com/community/c3208025_
October 12, 2024
spheregeometry3D geometry
Problem Statement
Prove the following theorem:
If the intersection of any plane that has more than one point in common with the surface is a circle, then is a sphere (surface).