Only if they belong to congruent circles.
Are congruent circles.
You need only know the radius of each circle to determine that they are congruent. If the radii are identical, the circles are identical. This can also be determined by comparing the diameters (twice the radii), or the circumferences, or the areas of the circles. In all cases, if the parameters are identical, the circles are identical.
If they're in the same circle or in circles of equal radii (radiuses), then yes.
a cylinder has two faces that are circles
Congruent circles, maybe...
They are arcs of congruent circles.
The same radius.