Answer:
Circle
Explanation:
We have been given a definition and we have to identify this definition belongs to which shape.
Think of a shape which has a well defined center and all the points on its boundary are at an equal distance from the center. Only one such shape exists i.e. Circle.
The boundary of a circle is its Circumference. Each point on the circumference of a circle is at an equal distance from the center of the circle and this distance is known as the Radius of the Circle.
Therefore, the answer to this question is Circle.