congruent
Circles with the same radius are congruent circles.
eyeballs
concentric circles
Concentric circles are circles with the same common centre.
Concentric circles
Circles with the same radius are congruent circles.
mandorla or vesica piscis (if they have the same radius)
2 circles can be congruent. The have to have the same radius.
eyeballs
Yes, it is true. Any circles with the same radius will have the same circumference as well.
congruent circles
The same radius.
No. You can only define a circle by radius, diameter, area, perimeter. Concentric circles have the same centre, therefore, if they were the same circles with the same radius, then they would all lie on top of each other and be effectively one circle.
No. Concentric circles have the same centre but not [usually] the same radius. Congruent circles have the same radius, but not [usually] the same centre. If you have two concentric congruent circles one will be exactly on top of the other.
No, it's not true that all circles with a radius of 0 cm have circumferences of the same length because a circle with a radius of 0 cm is actually just a point. A point does not have a circumference, as circumference is defined for circles with a positive radius. Therefore, circles with a radius of 0 cm do not exist in the traditional sense of geometry.
They are said to be concentric circles.
If you create third circle with radius 2, then all the points on that circle would be equidistant form both circles. So the answer is a circle with radius 2.