Answer:
⇒ Radii of congruent circles are equal
Explanation:
Congruent Circles : The circles which are similar and equal to each other are called congruent circles. So, radius of the congruent circles are equal.
Concentric circles : The circles which have the common center is called concentric circle. So, The radius of the concentric circle may be different. So, this is rejected.
Coplanar circles : The circles which lie in the same plane are called coplanar circles but the radius of the two circles lying ion the same plane could be different so this case is also rejected
Overlapping circles : The circles which overlap each other are known as overlap circles but overlapping does not show that their radius will be equal. So, this option is also rejected.
Hence, The correct choice is Congruent
⇒ Radii of congruent circles are equal