The third postulate states that its possible to draw a unique circle given a center and radius. Here, a circle is defined to be the curve such that the distance between any point on it and the center is always equal to the radius. On a sheet of paper, this is the establishment of the compass, and once again is quite obvious. In spherical geometry, a circle is just Euclidean circle but with a different Euclidean radius than its spherical radius. In the Poincare Disk, a hyperbolic circle is also just another Euclidean circle, and this is a general property of stereographic projection. However, the Poincare metric results in the Euclidean center of a hyperbolic circle being offset from its hyperbolic center, and the Euclidean radius differing from the hyperbolic radius. This is shown in the next interactive: