A circle is a shape consisting of all points in a plane that are at a
given distance from a given point, the centre; equivalently it is the
curve traced out by a point that moves in a plane so that its distance
from a given point is constant.
In Euclidean geometry, any three points, when non-collinear, determine a
unique triangle and simultaneously, a unique plane (i.e. a
two-dimensional Euclidean space).
Don't be a ...