- Circle[Point M, Number r]
- Yields a circle with center M and radius r.
- Circle[Point M, Segment]
- Yields a circle with center M and radius equal to the length of the given segment.
- Circle[Point M, Point A]
- Yields a circle with center M through point A.
- Circle[Point A, Point B, Point C]
- Yields a circle through the given points A, B and C.
| Following text is about a feature that is supported only in GeoGebra 5.0.
Note: From GeoGebra 5, this command will work with 3D objects as well
Use circles to fix the distance between two objects
Circles are a great way to make the distance between two objects constant: If there are two points A and B on two lines g (point A) and h (point B) where A can be moved and B should have the constant distance r to A you can define B as the intersection between the line h and the circle around A with the radius r. As a circle intersects a line at two points (in case it's not tangetial or passing by) you have to hide & ignore the second intersection.