How a straight line is an infinite circle
- Author:
- John Brennan-Rhodes
- Topic:
- Circle
Move the blue points on the sphere to edit the three points defining a circle.
See what happens when the points are co-linear.
The sphere represents stereographic projection where infinity in all directions are mapped to a 'point at infinity'. https://en.wikipedia.org/wiki/Stereographic_projection
See the "Riemann Sphere" file for a follow up activity.